That might, however, make him no longer retain his original form, so then he's seriously dead, and the horcruxes activate.

Possibly true; although I’m not sure whether Voldemort’s spirit would still stay inside the jewel once that transfiguration is made permanent. (Less of a problem now, thanks to the obliviation, but I’d still prefer some oversight, just to be safe.)

Both good points. While Harry does actually have the means to overcome that difficulty, I admit I hadn't thought of it in the first place. Up-votes for both.