I love the theme, but what happens if I use a soul which gave me a prerequisite for another feat (if I killed someone to get spell focus conjuration and then got augment summoning) to stop my death? Does the feat vanish, or do I have to sacrifice the highest level soul? And since untyped bonuses stack, can't I just go on a rampage and kill hunredes of peasents (making a small army of zombies) and gain some ungodly bonus to craft?