Ok. So here is the hidden premises that I didn't show.
1. If Allah clarified Succession and Leadership, he should also have a firm manifest proof of which sect that believe in Imammate is right.
2. It would be incumbent upon him to clarify the number and names as that the only way to have a manifest proof of which sect that believes in Imammate is right.
3. The only number given in ahadith attributed to the Prophet with names is 12 and the only names that correspond to that is 12 Imams.
4. The same is true of all nations before, they would have to know how many chosen leaders succeed their founding Prophet even if those leaders are Prophets themselves.
5. The only possible number shown in the past regarding succession and covenant, is twelve.
6. Hence it follows, if God clarified the issue of leadership and succession, it would be Twelver Shiism that is correct.
1. If Allah has clarified leadership and succession it does not follow that he would provide a proof for which sect is correct, rather it would be upon the sect to provide it's own proofs for showing that it is in alignment to the words of Allah. Case in point, where Allah has specifically stated the issues of the religion (Prayer, Fasting, Hajj) no people from the people who face the Qiblah dispute that these are actions that are supposed to be obeyed; we disagree on everything else - including leadership and succession ergo this was not clarified.
2. No it would not - Allah doesn't mention the names of all the prophets nor the various revelations that they received ('aliehum as-salam) yet it is incumbent upon all to believe in them.
3. There is a Hadith in Bukhari where the propher (sal allahu 'aliehi wa salem) says:
"The Israelites used to be ruled and guided by prophets: Whenever a prophet died, another would take over his place. There will be no prophet after me, but there will be Caliphs who will increase in number." the word
فيكثرون is used which signifies a great number not 5, 7 or 12.
4,5&6. If your only criteria is that there is a hadith which says 12 and you believe in 12, it is a poor argument to be sure - for argument sake today I now accept 12 Imams from Quraish here are their names:
1. Ali ibn Abi-Talib
2. Al-Hasan
3. Al-Hussayn
4. Mohammed ibn Hanafiyya
5. Ali ibn Al-Husayn (Zayn Al-Abideyn)
6. Zayd ibn Ali (Ash-Shaheed)
7. Jafar ibn Mohammed (As-Sadiq)
8. Mohammed ibn Abdullah ibn Hasan ibn Al-Hasan (An-Nafs Az-Zakiyya.)
9. Abdullah ibn Jafar (Al-Aftah)
10. Mohammed ibn Jafar (Ad-Dibaj)
11. Musa ibn Jafar (Al-Kadhim)
12. Jafar ibn Ali (brother of Hasan Al-Askari) - 'Aliehum As-Salam.
All the above are from Quraish and also the family of the prophet (sal allahu 'aliehi wa salem), just in case that is going to be your next criteria - how are they disqualified from this hadith? Or any of the other 'Alids and truth lovers who rose and fought for the pleasure of Allah?
Regards,
Glorfindel.