With his own resurrection, he’s transfiguring stuff into his body, using the Stone to make the transfiguration permanent, then having his spirit repossess the body.
With Hermione, the body was never the problem. Where’s he getting the spirit? How does the Stone help?
Harry’s Patronus appears to have solved that problem, although we don’t know how. “Not another Tom Riddle” suggests that it worked.
How does the Stone help?
Hermione’s body needs significant repair, and the only way we know of for the repairs in question (once the person is dead) is permanent Transfiguration.
But that suggests that you can resurrect someone non-permanently without the Stone—and possibly keep them alive indefinitely by expending constant magic on it like Harry does with his father’s rock.
I would guess that the True Patronus would fail in that case, because it is no longer true that “the only thing wrong with this body is that it’s dead.”
Electricity and drugs would probably have produced muggle-Hermione. Probably the system doesn’t assign new usernames to beings that appear out of thin air except for patroni, and Hermione’s account is long-retired in any case.
How is Voldemort resurrecting Hermione?
With his own resurrection, he’s transfiguring stuff into his body, using the Stone to make the transfiguration permanent, then having his spirit repossess the body.
With Hermione, the body was never the problem. Where’s he getting the spirit? How does the Stone help?
Harry’s Patronus appears to have solved that problem, although we don’t know how. “Not another Tom Riddle” suggests that it worked.
Hermione’s body needs significant repair, and the only way we know of for the repairs in question (once the person is dead) is permanent Transfiguration.
The body still needed to be restored to the state of a complete and healthy body, and the Stone made it permanent.
Presumably, the body was repaired to true health—which also means that the brain was restored to its original state, that is, functional.
At that point, a Muggle can be revived by simply restarting her heart. A witch, apparently, requires a bit of magic.
But that suggests that you can resurrect someone non-permanently without the Stone—and possibly keep them alive indefinitely by expending constant magic on it like Harry does with his father’s rock.
I would guess that the True Patronus would fail in that case, because it is no longer true that “the only thing wrong with this body is that it’s dead.”
Electricity and drugs would probably have produced muggle-Hermione. Probably the system doesn’t assign new usernames to beings that appear out of thin air except for patroni, and Hermione’s account is long-retired in any case.
The brain contains all the necessary information, I don’t think a “soul” is needed.