That pretty much still is same in my gamepay. I kept him alive and he never died in any situation. Still standing like an idiot and quest never completing either.I'm guessing you make a deal with Gurtak in the Outpost.
Witchcraft wear off by the time you have your final fight with Tia's dad. If he dies, "Revenge" get settled. I don't know if he can not die in that fight.
If I'm not mistaken, if Gurtak ends up dead in any of the fights during the game, or you decide to kill him, "Revenge" get resolved.
I don't know about the belt.