Excellent questions, I'm glad you asked.
First, is it true that Zain Al-Abedin was declared the 4th imam by the ladies of the Household?
I doubt it. Only Allah knows best.
Zain al-Abedin was born in 659 AD (38 AH) and died 713 AD (95 AH) at age 54. Battle of Karbala was fought in 680 AD (61 AH). Thus according to the calculation from these figures, he was 21 years of age during the battle of Karbala, nearly 22. The strategy of Yazid’s army was not to leave any male member of Hussein’s family alive during the battle of Karbala. Altogether over 70 males of different ages were martyred. So I don’t know how a 22-year-old man so closely related to Hussain bin Ali’s family could be taken as prisoner despite being declared the “
fourth imam.” I really don’t know how Yazid’s forces could have allowed that to happen right under their noses. From what all reliable historical sources tell us is that all prisoners taken from the camp of Karbala, after the martyrdom of Hussain and his comrades, were women and children of his household. Even in the Iranian movie with English subtitles, “
Caravan of Pride,” which depicts the aftermath of Karbala, does not show any adult male survivors taken prisoner. Yet how did a 22-year-old healthy male of the family survive and become Hussain’s successor is something no one has bothered to explain.
Secondly, Is there any truth that Zain al Abedin was the son of Imam’s Hussein’s third wife was ShahrBanu, a Persian princess of the Sassanid dynasty and probably converted to Islam later? Actually even Wikipedia and every other sources puts this information as very controversial.
Completely false. Iman Hussein had two wives, Rabab and Laila. Both were from the Arabian peninsula. Furthermore how on earth would he ever meet a Sassanid woman in Persia when he had never even stepped foot on that land all his life? And surely no Sassanids, particularly their so-called royalty, came to the Arab world either. This is a story woven by mainstream much later by twelver Shiias of Iran to create a link between Imam Hussein and Persia / Iran. Many Iranians especially of earlier times discriminated bit between themselves and the Arabs with a condescending attitude. Yet the fact was, and is, that Hussein bin Ali and his family were Arabs not Persians. Hence, arose the need for them to fabricate history that he had a Persian wife and Zain Al-Abedin was her son. He was not her son for the simple reason that no one knows who "Shahrbanu" was, let alone being the wife of Imam Hussein. Zain Al-Abedin was born and raised in Medinah. There is absolutely NO historical record nor evidence of any foreign (non-Muslim Persian) woman by the name of ShahrBanu living in Medinah as wife of Imam Hussein and the mother of one of his sons. None whatsoever. Zain al-Abedin was the either the son of Rabab or Laila as there is no confirmed data as to how many children he had from both his wives.
The twelvers of Iran are no better than the Bukhari & co. in concocting and designing lies for the purpose of manipulating facts to suit their interest, one way or another. After all, Bukhari was also none but a Persian.