Interestingly using the CR calculator the trooper combat was only worth 220 XP for the group even when added extra for ambush and advantage Likely I use rewards on task completion bases, not on combat.
Theo might have to kill Vader if he can't reason with him and take whatever happens, without his soul gem though it's very possible any powers of this place will just smite him dead, and that it for him. He has 1 trick he can use to save himself if that happens.