The reason that Pāli, e.g. Brahmanimantanikasutta, is quite hard to translate.

That's right. It's a bit hard for the translators. 
1. In a normal context, viññāṇa-noun (or the words in the center or end of sutta like that) appears in the same form before, but in this sutta it came in the different form, jānāti-verb. 
2. Pāli is an oral tradition language. The speaker can abstain the word that already spoken in the previous paragraph because he and the listener are knowing it. But when the others, e.g. Ānanda, listen to it, reciting and the explanation, Atthakathā, is required. 
Therefore, even we can read Pāli and Atthakatha, the reciting and memorizing still required.

Buddhist objective is nibbāna, the safest, so the reader need to learn it hard step by step

Buddhist objective is nibbāna, the safest.
It's like the science's, engineering's or computer programming's rule, we can't misunderstand at any level of the process. It's buggy, risk and unsafe.
Therefore, it's very hard to understand Tipitaka and Atthakatha as alike as science's, engineering's or computer programming's rule.
So, if you point your expectation in Buddhism only at the easy part, you will miss the safest part, which elaborated multi aspects of reasons. That missing is buggy, risk and unsafe.
So, concrete exposition of Buddhism is the conclusion like:

1. Vinaya is in VN Parivāra by upāli, the vinaya secretary of buddha.
2. Sutta is in KN Paṭisambhidāmagga by sāriputta, the stand-in teacher of buddha in MN Mahāgosiṅgasālasutta (or alternative in translated Visuddhimagga but if you bias of the supernatural, it's not your choice).

Both above require these to understand:

1. Pāli skill from Kaccāyana.
2. Tipitaka analysis skill from Netti.
3. The discipline of everything from abhidhamma by sāriputta, the stand-in teacher of buddha in MN Mahāgosiṅgasālasutta. Or, saṅgaha by anuruddha, past laṅkā's pontiff.

But if you want to start in Buddhism, you need:

1. Qualified teacher to teach you step by step.
2. Easy sutta to recite and do follow, such as Maṅgalasutta (and all Khuddakapātha), Siṅgālakasutta, and dhammapatha.

(Must read!) No lokuttara arūpa, Words' relation about lokiya&lokuttara jhāna

Therefore, lokuttara-appanā jhāna has not arūpa-state, lokuttara-nibbāna are over all aggregates, paṭicca-samuppāda cessation at all. That means there is no rūpa-object or arūpa-object for lokuttara-appanā consumer to think out of, no object for meditation, because the nibbāna-object, of lokuttara-appanā-jhāna, has already out of all aggregates.

The explanation of meditation's relative words:

Pāli words relation: The paṭipanno bhāvanā samādhi by doing jhāna of samatha-ārammṇa. The comparative of bhāvanā's paricita called (nānā ārammanāni) khaṇiko samādhi, the upacāra of samādhi to samāpatti the ekagga-bhāva, and the upacāra of samādhi to samāpatti the ekagga-bhāva. (I used all of pāli word as nāma-sadda to avoid vibhatti's variation, but ). Ekaggatā is eka-bhāva of citta that has eka-rāsi of cetasikasampayutta and eka-ārammaṇa.

The translation of above pāli words relation: The practitioner meditates concentration-meditation by watching samatha-object. The comparision of meditation's evolution called various-object-momentary concentration, almost-consummated-one-pointedness concentration, and already-consummated-one-pointedness concentration. The one-pointedness is the state of mind that has only one same set of mental factors and only one-object continuously arising.

Lokiya = Under Aggregates' Dependency, paṭiccasamuppāda.
Lokuttara = Over Aggregates' Dependency. Lokuttara-aggregates are over present&future taṇhā aggregates, and future resultants. Lokuttara-nibbāna are over all aggregates.

By Abhi. Vibhaṅgo, Samāpatti (consummation) means bhāvanā (meditation). By Mettānisaṅsasutta, it's atthakathā, and Visuddhimagga, bhāvanā (meditation) means the meditation minds continuously arise without the barrier, hindrances.

So, lokuttara-samāpatti means the consummation of lokuttara-citta meditation. And lokiya-samāpatti means the consummation of lokiya-citta meditation.

What is appanā of one-pointedness?

The practitioner meditates the meditation to be proficient (samāpatti). The professor (samāpanno) of the meditation can think of the meditation object without bhavaṅga, five hindrances, and the letting go object. This is why the one-pointedness can be the state of mind that has only one same set of mental factors and only one-object continuously arising.

What is the difference of Lokiya Appanā VS Lokuttara Appanā?

Note: this is just the comparison. But in the real situation, virtual mind&concentration mind&insight mind switch each others to arise depend on the environment of the meditation. The purified virtual and purified concentration (visuddhi) arise automatically in the proper situation because to support the Insight meditation. This is the reason why taṇhā-carita practitioner should meditate concentration meditation specially, his concentration must ready to arise automatically in the environment that five hindrances, pariyuṭṭhāna-kilesa, can arise to hinder all meditation. The concentration mind must automatically arise before the hindrances arise to destroy the meditation.

Lokuttara Appanā
Practitioner is 4 Mahākusala/4 mahākiriyā mind with 33 mental factors.
Practitioner's object is Whole five aggregates in dependent origination cycle for the appearance of three normal characteristics.
The enemy is whole future 14 arise-able unwholesome (anusaya-kilesa) especially avijjā, lobha, dosa, sakkāya-diṭṭhi.
Enlightenment is 40 lokuttara appanā minds with 36 mental factors 40 which knowing only nibbāna.
Enlightenment's object is Nibbāna-object which is the opposite of whole five aggregates.

Lokiya Appanā
Practitioner is 4 Mahākusala/4 mahākiriyā mind with 35 mental factors.
Practitioner's object is the pair enemy-object of specific present unwholesome (pariyuṭṭhāna-kilesa), such as asubha-meditation is the couple of subha-kāmarāga hindrance.
The enemy is the whole present 14 arise-able unwholesome (pariyuṭṭhāna-kilesa) especially 5 hindrances.
Consummation is 27 lokiya appanā minds with 35 mental factors which knowing only that pair enemy-object of specific present unwholesome (pariyuṭṭhāna-kilesa).
Consummation's object is the pair enemy-object of specific present unwholesome (pariyuṭṭhāna-kilesa). Some of them are the realities, some of them are paññatti:

1. Because five strings (paṇcakāmaguṇa) are variant reality at five senses, the rūpa-jhāna practitioner must think of the unlimited enemy imagination (paññaiti-object) of five string realities to avoid the five-string-reality thought. But rūpa-jhāna concentration base on the matter, the jhāna's element-pausing effort is not the cause of getting arūpa-object. The rūpa-jhāna consumer can get arūpa-object after his jhāna-power is strong enough.
2. Because out of the paused jhāna-elements, the fifth rūpa-jhāna consumer's ability is ready to think without any matter, the fifth rūpa-jhāna consumer can meditate arūpa-jhāna from now on.
3. Because every paññatti-object of rūpa-jhāna base on the collection of five strings (seven gocara-rūpa), this jhāna consumer still be easy to return to attach five strings again. So, the fifth rūpa-jhāna consumer must try to think out of every five strings by thinking of arūpa-jhāna object. Letting matter go because nothing of arūpa-jhāna object relating with matter.

Therefore, lokuttara-appanā jhāna has not arūpa-state, lokuttara-nibbāna are over all aggregates, paṭicca-samuppāda cessation at all. That means there is no rūpa-object or arūpa-object for lokuttara-appanā consumer to think out of, no object for meditation, because the nibbāna-object, of lokuttara-appanā-jhāna, has already out of all aggregates.

See this article.

The relation of lokuttara/lokiya/citta/viññāna/mano/paññā which sariputta used as a base of abhidhamma-literature.

If consciousness is a Reification, how does a Buddha attain the Truth?
'Reification' is making something real, bringing something into being or making something concrete.
The Pali suttas say about the relationship between consciousness and wisdom/enlightenment:

Discernment (wisdom; panna) & consciousness are conjoined, friend, not disjoined. It's not possible, having separated them one from the other, to delineate the difference between them. For what one discerns, that one cognizes. What one cognizes, that one discerns. MN 43

Is the Enlightenment or Wisdom of a Buddha a Reification?

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The question make a wrong comparison. It's a totally different story.
From question's quote, ven. Sāriputta in Ma. Mū. Mahāvedallasuttaṃ (MN 43) is talking about minds&wisdoms, which are clinging-aggregates of run-of-the-mill person before enlightenment; But from question's asking, enlightened minds&wisdoms of Buddha are minds&wisdoms after enlightenment, so Buddha's enlightenment-wisdoms are declung-aggregates of the noble one.

1. Question's quote is declung-aggregates:

Declung-aggregates in Sutta. Saṃ. Sa. issatthasuttaṃ:

The entire spectrum of an adept’s ethic-aggregate, immersion-aggregate, wisdom-aggregate, freedom-aggregate, and knowledge&vision-aggregate of freedom.
Asekkhena sīlakkhandhena samannāgato hoti, asekkhena samādhikkhandhena samannāgato hoti, asekkhena paññākkhandhena samannāgato hoti, asekkhena vimuttikkhandhena samannāgato hoti, asekkhena vimuttiñāṇadassanakkhandhena samannāgato hoti.

Declung-mind-aggregates in the end of Sutta. Saṃ. Kha. Anattalakkhaṇasutta:

And while this exposition was being given, the cittas of the group of five bhikkhus, by not clinging, were liberated from the āsavas.
Imasmiñ·ca pana veyyākaraṇasmiṃ bhaññamāne pañca·vaggiyānaṃ bhikkhūnaṃ anupādāya āsavehi cittāni vimucciṃsūti.

Declung-wisdom-aggregates and declung-mind-aggregates in Sutta. Ma. U. Mahācattārīsakasuttaṃ:

“And what, bhikkhus, is right view that is noble, taintless, supramundane, a factor of the path? The wisdom(paññā), the faculty of wisdom, the power of wisdom, the investigation-of-states enlightenment factor, the path factor of right view in one whose mind(citta) is noble, whose mind(citta) is taintless, who possesses the noble path and is developing the noble path: this is right view that is noble, taintless, supramundane, a factor of the path.

2. But question asking about clinging-aggregates:

Clinging-wisdom-aggregates in Sutta. Ma. U. Mahācattārīsakasuttaṃ:
“And what, bhikkhus, is right view that is affected by the taints, partaking of merit, ripening in the acquisitions? ‘There is what is given and what is offered and what is sacrificed; there is fruit and result of good and bad actions; there is this world and the other world; there is mother and father; there are beings who are reborn spontaneously; there are in the world good and virtuous recluses and brahmins who have realised for themselves by direct knowledge and declare this world and the other world.’ This is right view affected by taints, partaking of merit, ripening in the acquisitions.
Clinging-mind-aggregates in Sutta. Tī. Ma. Mahāsatipaṭṭhānasuttaṃ Cittānupassanāpabba:

Here, bhikkhus, a bhikkhu understands citta with rāga as "citta with rāga", or he understands citta without rāga as "citta without rāga", or he understands citta with dosa as "citta with dosa", or he understands citta without dosa as "citta without dosa", or he understands citta with moha as "citta with moha", or he understands citta without moha as "citta without moha", ...

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Note: Citta (mind), mano (intellect), and viññāna (experience/consciousness) are same, according to Sutta. Saṃ. Ni. assutavasutta:

"But as for what's called 'mind,' 'intellect,' or 'consciousness,' the uninstructed run-of-the-mill person is unable to grow disenchanted with it, unable to grow dispassionate toward it, unable to gain release from it...

The reason that why paṭisambhidāmagga-pāli by sāriputta is the best dhamma explanation

This topic should not strict in english version only, because the best buddhist book maybe didn't write in english.

I recommend paṭisambhidāmagga-pāli by sāriputta.

Content:

Clearly explanation of every important dhamma, which often appear in sutta, such as ñāṇa, dhammacakkappavattanasutta, vipassanā, pariññā, samatha, sīla, etc.

Reasons:

Sāriputta is in the middle of budhha, upāli, ānanda, atthakathā, buddhagosa, thai monks, and myanmar monks. So, if you can understand his concept, you can understand the whole theravāda canons.

The referene for above reason:

1. Sāriputta is tipitaka-memorizer who born in the same time with the buddha.
2. Sāriputta was announced by the buddha as the best teacher in Ekanipātā, Ekapuggalapāli:

   Bhikkhus, I do not know of any other person who could follow up the teaching proclaimed by the Thus Gone One other than Sāriputta.

   Bhikkhus, Sāriputta follows up the teaching proclaimed by me.

3. In the introduction of dīganikāya's atthakathā wrote that sāriputtas' students were co-designers of tipitaka's structure.
4. In Sutta. Ma. Mū. Mahāgosiṅgasālasuttaṃ, every leaders of 1st saṅgāyanā's members such as, kassapa, ānanda (sutta-memorizer), anuruddha, upāli (vinaya-memorizer), and their students (memorizer of abhidhamma and athhakathā), often go to listen sāriputta's dhamma explanation.
5. Budhhagosa used paṭisambhidāmagga as the main reference when he authored the path of purification, visuddhimagga.
6. The tipitaka-strict monks in Thailand and Myanmar are using visuddhimagga as the main reference to access tipitaka.

The advantage of reciting and memorizing

Actually, we can found the relativity of words every where in tipitaka.

When we recited and memorized pāli, we will see the relativity between words, meaning, sutta, section, nikāya, pitaka, antedate&
predate cannons. This relativity is called "holding together by a thread (suttena susaṅgahitāni)" in nidāna of V.N. Verañjakaṇḍa. And it is what mahāsāvaka did in buddha's time and at 1st saṅgāyana. So, when buddha still alive, he complimented them in A.N. Ekakanipāta, Etadaggavagga. Because they helped him to describe his teaching (in their own schools), and he knew by sabbaññutañāṇa "these professional monks will relatively categorize my teaching to let it going on for 5000 years".

The tipitka professors never explain us this reason, because they recited and memorized pāli, so they never found the serious conflict between the cannons, just the through-reader especially translation version, often make the nonsense doubts.

Saṇkhāra-cause, Saṇkhata-effect; So, we don't need to find that Where is Nibbana/Nirvana being Unconditioned stated in the Canon?

You can see these pali-words everywhere in canon. This is the reason that why I often told everyone to recite and memorize pali canon.
Saṇkhata (5 aggregate-effects) means it is caused, is conditioned, by 5 aggregate-causes.
Saṇkhāra (5 aggregate-causes) means it causes, conditions, 5 aggregate-effects.
Saṇkhāra-paṭiccasamuppāda (kamma-bhava, karma) means it causes, conditions, becoming (jāti, upatti-bhava, 5 khandha).
Asaṇkhata (nibbāna) means it is unconditioned by any saṇkhāra.

How to find the right Dhamma teacher

I tried to follow everything from the nissayamuccaka-course which I described in this answer, when I was still in a monk-hood by myself; and I had a low-quality teacher for about five years; before I found a perfect teacher from pa-auk forest monastery (this monastery also published other English-language Dharma articles here) who have all of the qualities listed below, that were specified in the tipitaka and commentary.
I met the pa-auk teacher too late, so I am being a layman now. However, it was my previous effort and experience which gave me the confidence to choose pa-auk to be my kammaṭṭhāna teacher.
The qualities of a teacher, and the operating procedure to choose and to apply with the teacher, have been briefly described in Chapter 4 of the Path of Purification.
Furthermore, in my opinion, the significant quality of a teacher is paṭisambhidā: because all ariya must have paṭisambhidā, at least in his kammaṭṭhāna. So he should have these qualities:

1. His teacher descent, he must derived from a tipitaka memorizer (buddha-sāvaka, suta-buddha; V.N. Mahāvagga Nissayamuccnakathā).
2. His enlightenment, he must achieved at least upacāra-samādhi and balava-vipassanā (4 paṭisambhidā; V.N. Mahāvagga Nissayamuccnakathā).
3. His tipitaka memory, he must graduated through at least nissayamuccaka-course (V.N. Pācittiyakaṇḍa Ovādakasikkhāpada's commentary).
4. His tipitaka understanding, he must not cut tipitaka off or make tipitaka conflict each other. Because tipitaka was memorized by single commentary teacher group at 1st saṅgāyanā, so it must be a single package that compatibility with each other (pro in tipitaka relation, dhamma-paṭisambhida&attha-paṭisambhidā).
5. His pali skill, he must understand pali in advance (nirutti-paṭisambhidā).
6. He must be a genius one (paṭibhāna-paṭisambhidā).

Furthermore, in tipitaka and commentary tradition, since mahākhandhaka of vinaya mahāvagga is completed authored by upāli in 1st saṇgāyanā, all layman's teachers must have all of these qualities, that concluded by upāli in bhikkhunovādakasikkhāpada's commentary (which I translate below as follows):

Qualities of nissayamuccaka-bhikkhu (teaching lay people)

1. Proficient to recite pāṭimokkha-pāli and to understand it's commentary.
2. Proficient to recite and to understand 4 bhāṇavāra (~1,000 syllable) of sutta and their commentary, to teach laymen on uposatha day.
3. Proficient to recite and to understand sutta for bhikkhu's life such as andhakavindasutta, mahālahulovādasutta, ambaṭṭhasutta, etc.
4. Proficient to recite and to understand sutta for teaching in 3 chances: banquet for saṅgha by layman (nidhikaṇdasutta), funeral ceremony (tirokuṭṭasutta), and auspicious ceremony (maṅgalasutta).
5. Enough understand to judge/to decide about saṇgha's ceremony such as uposatha, pavāraṇā, etc.
6. Proficient to recite and to understand his kammaṭṭhānā throughout the nibbāna-course.
7. 5 years experience in monk hood as a monk.

Qualities of bhikkuparisūpaṭṭhāpaka-bhikkhu (teaching bikkhus)
If above layman's teachers want to teach bhikkhus (ūpajjhā-ācāriya, nissaya-ācāriya), they must increase their skill level to all of the following qualities.
These are for abhivinaya teaching:

1. Proficient to recite mahāvibhagha and bhikkhunivibhaṅga (first 3 books of thai 45 books pali-tipitaka) of vinaya-pitaka-pali. At least, he can relay with the other 3 bhikkhu. Proficient to understand it's commentary, too.
2. Proficient to recite all saṇgha's ceremony in vinaya-pitaka mahāvagga and julavagga.
3. Proficient to recite 14 vatta in vattakhandhaka.

These are for abhidhamma (kammaṭṭhāna) teaching:

4. Proficient to recite one of this suttanta-pali: mūlapaṇṇassa (1st/3 parts of M.N.) for student in M.N. faculty, mahāvagga (2nd/3 parts of D.N.) for student in D.N. faculty, sagāthavagga+nidānavagga+khandhavāravagga of S.N. or mahāvagga of S.N. for student in S.N. faculty, before half of A.N. or after half of A.N. or ekakanipāta+dukanipāta of A.N. for student in A.N. faculty, jātaka+commentary (because kammaṭṭhāna was described in commentary) for student in jātaka faculty.

Qualities of bhikkunovdaka-bhikkhu (teaching bhikkunīs)
If above layman's teachers want to teach bhikkhunī, they must increase their skill level to all of these qualities:

1. Proficient to recite whole tipitaka-pali and commentary-pali. Or at least, he still must recite whole tipitaka, but he can recite just one commentary of suttanta, first 4 parts of commentary of 7 parts of abhidhamma. However, vinaya-commentary is what he must recite it all.

Reference: tipitaka and commentary of vinaya pācittiyakaṇḍa bhikkhunovādakasikkhāpada and vinaya mahāvagga mahākhandhaka.

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(I still find it difficult to reference the tipitaka and commentary using english resources: there's no translation, very long pages, confused categories, cutting some parts off the tipitaka, cutting commentary off from pali canon, etc.)

Related topic: https://buddhism.stackexchange.com/questions/3163/should-lay-buddhists-teach-the-dhamma

Layers of pali literality already being in buddha-living-period

Layers of pali literature already being in buddha-living-period.

There are many pali literature in buddha's time, such as buddha's literature, sāriputta's literature, mahākaccāna's literature, upāli's literature, etc. Because every mahāsāvaka have there own students.

But the most influential literature are buddha's literature and sāriputta's literature.

4 nikaya are buddha's literature, most of the others cannon are sāriputta's literature, because he is the one who buddha said "sāriputta is the best teacher who can teach like me". So everyone always go to meet sāriputta to listen his teaching, in his literature. But if someone need buddha's literature, they will go to meet buddha or ānanda, who is the best in sutta memorizing.

So, abhidhamma is difference from sutta, because commentary said "abhidhamma is memorized by sāriputta". And the other buddha's sāvaka book also have literature look like sāriputta's literature because everyone in buddha-living-period often go to learn dhamma with sāriputta (see:mahāgosiṅgasālasuttaṃ).

7 Vinaya-pitaka, is memorized by Upāli and his students. He also author some path of parivāra because buddha said in tipitaka (a.n.) "Upāli is the best vinaya-memorizer" (vinayadharānaṃ yadidaṃ upāliฯ).

Suttanta-pitaka is memorized by Ānanda. But in 1st saṅgayanā, 500 arahanta decide to separate whole sutta to 4 nikya.Then they gave each nikya to a group of 4 etadagga and his student to especially memorize it.

Who are the members, of group of 4 etadagga? Ānanda and his students (tn), Sāriputta's students (mn), Kassapa and his students (sn), Anuruddha and his students (an). (The others have learned and memorized dhamma, too, but buddha said "ānanda is the best", so everyone need him in 1st saṅgayanā).

Abhidhamma-pitaka, paṭisambhidāmagga, niddesa, buddhavaṃsa, cariyā-pitaka, except kathāvatthu of moggalliputta, is learned by Sāriputta, But then they are memorized by every arahanta, because everyone in buddha-living-period often go to listen Sāriputta (see:mahāgosiṅgasālasuttaṃ).

Origin: http://www.tipitaka.org/romn/cscd/s0101a.att0.xml