Dear Avira,
I’m looking for sources that say after this point in time, every prophet that comes along is obviously a false one. Where does it say that? It would have saved us a lot of grief.
I don’t know to what extent the Rashba rejected him. I don’t understand your question.
The Arizal redid all of Kabbalah. The main purpose of Eitz Chaim was to weed out the illegitimate. If these methods were not valid stuff, they may have slipped through a bit. There wouldn’t be a whole section dedicating to preserving them.
I don’t know why you feel threatened by the existence of prophecy at all times.