^Bhaijaan, it all boil downs to number 4.
Whom you consider prophet, we do not. And you would agree that anyone making a false claim of prophethood is out of fold of Islam.
So if it boils down to this. Then, we consider "ALL PROPHETS" are from Allah including the one whose advent was prophecied by AnHuzur (saw) 14 plus hundred years ago.
But as you said, you do not believe in that prophet. So, then decide for yourself, by definition, who goes outside the fold of Islam?