I really can't think of there being any way for the items to work aside from the sword. The sword wouldn't be stealing anything though, they'd have built-in spells they can cast with a single action. As for the homunculus thing, wanting a really good bodyguard is a good reason. As for spirits and souls... Well, spirits are different from souls since they're not just life energy. The only thing I can think of that's like that is outright possession.