True enough, but the injuries he had in DD were worse than in College Arcane. Also he had had three days to heal already, using healing glyphs & his aunt’s charms, so by the time Tanya gave him some blood, he didn’t need a whole lot of healing, being mostly stiff & sore. Remember he was strong enough to fight Dellwood that morning.
It seems he would still be able to use magic, but the cellular mechanism allowing magic, were or vampire powers would have to switch from one to the other. He can’t have accelerated healing while pulling external power. If he was turned into a were, he might be able to wolf out, but if he then used magic, there would be no fast healing. It may take time & need practice to do it fast & at will. Same thing with being a vampire probably, although Chris can use vamp powers as well as his aura & fast healing. Vampires do develop a talent(s) as they get older, so his vampire power could be magic. I think I speculated on this in the Thoughts & Questions thread.