Re: 12 Caliphs
I think that the twelve caliphs cannot be from Banu Ummaya as they were the ones who murdered Imam Husayn (as) and then afterwards jailed and murdered the descendants of Imam Husayn (as). The only leader from Banu Ummaya Kingdom after Yazid who I think deserves any respect is Umar bin abd' al-Aziz. But he is not a Mujaddid.
I think we're forgetting here Sayyidina Imam al-Mahdi (as) a hasani-husayni Sayyid from the family of Sayyidina Rasul-Allah (saws) who is the Sahib uz-Zamaan, Sahib ul-Waqt, the awaited khalif....