Assalamu alaikum brother, We should follow the stronger opinion as Mufti Husain pointed out previously. Disregard the SunniPath fatwa. Shaykh Faraz mentions that a number of reliable ulema give fatwa on this weaker opinion without mentioning who these "reliable" people are so that we judge for ourselves if they are reliable or not. We have from our authorities both past and present (like Mufti Husain and Mufti Abdur Rahman Mangera) that the follower's prayer would not be valid if the imam's is not valid according to the follower. We cannot assume what the imam did. If we don't know we have to assume the imam's wudu and ghusl is valid according to our madhab, even if in his madhab he is not obligated to wudu and ghusl as in the Hanafi madhab (but I am assuming it will still have to be considered sunnah in his madhab). This is what I understood from what our imam related from Mufti Mas'ud who is a very brilliant mufti from Azaadville madressah. Unless we see or know for certain the imam's wudu/ghusl/salah is invalid according to us we should pray behind them.