Is it permissible to pray behind brothers who have barelvi aqeedah, Is it permissible/ advisable for a Muslim woman to marry someone of barelvi aqeedah.

In principle, if the Imaam has beliefs of Shirk, for example, regarding Rasulullah [Sallallaahu Alayhi Wasallam] as Aalimul ghayb like Allah or regarding Rasulullah [Sallallaahu Alayhi Wasallam] as Omnipresent, then it is not permissible to perform Salaat behind such a person.

If the Imaam does not have beliefs of Kufr and Shirk, then Salaat behind him will be permissible.

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai