Where is your way of praying derived from? How did that come about? Historical evidence would be nice.
If the current imam chooses, then what are the criteria? Does he get a wahi from God?
well before answering the questions, i will quote a hadith of Huzoor(S.A.W) in which he said that if we hold tight to holy quran and his ahle-bait then we won't go astray. So we don't question the decisions of the imam
i am sorry but i don't know when our way of praying changed from other muslims but since the time i was born, i have been praying the same way.. i do know that it was the imam's decision to change it so we don't question his decisions..
imam does not get a wahi from God like prophets did but he does have the same noor which every prophet and imam had so he chooses his next imam through his knowledge of noor.. maybe be ilham but i'm not a 100 percent sure.. he has divine guidance of course so he chooses the right successor..