I don't see why Possession is a solution to this. When you play TM in a Possession turn, you still trash it, the only difference is that it is set aside just after trashing. So it just visits the trash a little bit shorter than when you play Graverobber/Rogue.
Just to be sure: when I play KC-TM on a Possession turn with 3 other TMs in hand, the possessor only gets 4 golds once, right (because of the lose track rule)?