I'm with TheMouse on this one. It's about mortal practitioners, and about enforcement. Shapeshifting into a panther is legal (you can transform yourself) and killing someone with your claws is legal (that's not magic, that's claws -- there's a reason the Wardens kill with swords). Your emissary is in interesting territory -- that's probably a mortal practitioner doing the deed, but they're under the aegis of whatever political/supernatural entity they're an emissary for. I'd say it's a violation of the law as far as the Council sees it, but diplomatic entanglements will make enforcement difficult. But, there's also a "the-reality-of-how-breaking-the-laws-affects-you" side to the laws in the RPG, so I'd say you probably still get dinged by the 'Lawbreaker' effect, mechanically, regardless of whether or not you can evade the political consequences.
And yes, there will be (light) rules for hellfire and soulfire.
The grimoires will be every bit as rare as they are in the novels... unless the GM decides otherwise.