If you accept proof of Wilayah and Authority of Auli-Mohammad in Quran and hadiths that reached tawatur and are accepted by both sects, then it remains that it's upon Allah [swt] and his Messenger [sa] to provide clear proofs regarding this affair.
What does Waliyah mean in your belief? Is a limitation of a dozen men who attain ilm-al Jafar? If we go into epistemology, the Prophets received wahi as their source of knowledge directly from Allah. So we are ordered to believe in them. Then it was the Imams (ie Imams Ali and his two sons) who learned under them. Then the golden chain continues until Imam Ali Rida (as). Now the issue is with the Imam you numbered 9,10,11 and 12 these Imams did not spend enough time with their fathers to become Imams or to lead the Ummah. How can you convince me they were the most knowledgeable men of the time? What is their source of knowledge after their father's passed away?
The way to do that is to emphasize that since Prophethood has ended, and books from God aren't going to be revealed as a standing sign and proof of the person holding Wilayah specifically is through Rasool himself giving
Again how is Waliyah held? In the Sunni belief it was Imam Ali (as) who spend a lot of time with the Prophet (pbuh). So his source of knowledge would be considered outstanding.
1. Emphasizing On a number
2. Names of them according to that number.
We have only one set of names with one set of number emphasized by hadiths. Now of course if any sect would have such hadiths that they believed to be authentic, they would cease to be that sect. So the proof is in this rational that it would be clarified.
Just as God safeguarded the Quran, in the same, he has safeguarded that there is only one real set of hadiths naming all Imams that coincides with the number given by the Nabi. Not with standing copyist errors that might make the number of Imams 13 or 11 when the intended 12 but miscalculated, the number is only 12.
The issue is Imam Baqer (as) and Imam Jafar (as) never told the entire Ummah that they are the 5th Imam or the 6th Imam. Also when Imam Ali (as) got in power he never told the people who gave him bayah 'I am the only Calipah, and you must reject the rest before me.' On the contrary, there is a report in Al Kafi where the Mutazilla come to Imam Jafar and tell him to give bayah to Imam Nafs-az-Zakiyah (as). In that so called discussion, Imam Jafar tells the Mutazilla to reject the 3 Calipahs, whereas Imam Ali (as) never did this when he became a Calipah. Any explanation other than Taqiyyah? Again in that same ahadith Imam Jafar never mentions that he is the 6th Calipah, and there are 6 more to come.
Even in Najh Al Balagha there is not a single page which mentions the 12 Imams. I wonder why?
So what the 12ers like yourself is do is attack the 3 Calipahs, but even with all the attacks it still doesn't prove to me that there are 12 Imams. In fact, when you declare the 12th Imam to be imam of the time, I see that to be a contradiction toward the Quran.
Just like we have hadiths clarifying the obligatory Salah, how many of them are we to perform, and then the exact details clarified in the Sunnah.....we would expect the same is true of Wilayah.
The 12ers claim the 12 Imams were mentioned in the bible, but I find it strange how this was missed in the Quran. Also, all the fard salah are mentioned in the Quran, whereas the case with the 12 Imams only the first 3 are present when the Quran was revealed in regards to their purification.
The fact that no other sect has the names of the Imams included in numerous of hadiths they hold, and according to a number with many of the hadiths they hold, shows, just like there aren't different versions of Quran that are all together a different Quran, that God safeguarded the way to know exactly who the Ulil-Amr from this nation we have to recognize.
No other sect has this 12 Calipah ahadith. It might be sahih in Sunni books, but sadly so are ahadith such as Abu Talib being a non-Muslim nauzbillah. So just like how I reject that ahadith against Abu Talib which is Sahih, I also reject the 12 Calipah ahadith which again is not mutawatir. Likewise the same applies to ahadith which talk about the Mahdi. They too are exaggerated by the Shia sect, and they made their way into Sunni sources.