Just a thought about the first law - remember that "taking out" doesn't mean instant death for NPCs any more than it means deaths for PCs. If you take someone out with a spell you don't have to say "so he's dead", you could say "He's lying on the ground unconscious and bleeding" or something like that. You can also work with the GM to apply consequences that make the story more interesting than just "he's dead".
Absolutely true. Of course, the GM -- in order to reinforce the fact that a w:12 ball of superheated plasma is *not* a nonlethal weapon and ensure that frivolous misuse of lethal magic has consequences -- might choose to "conceed", stating that the target dies, the upper half of his torso burned away to ashes. Or he could simply disagree that the "taken out" narration for the victim of such an attack might result in a glancing blow to the skull that knocks the target out but leaves them alive. Or ... etc.
As to the question of who qualifies for First Law protection, my conclusion is that the formula works something like this:
If the target is monstrous by nature (rather than simply by choice), or
If the target's race is fully or partially supernatural in nature, or
If the target's race is not native to the (a?) material plane, or
If the target or the target's race is an aberration to the Natural Order, or
If the target or the target's race was created by someone/something other than the Authorized Powers That Be of the cosmology in question, or
If the target lacks sentience or a soul,
Then the target is not a "person" and lacks protection of the Laws.
I'm not sure that this is a 100% complete formula, but I think it is probably close. Thoughts?