Not wanting to give anything away, I would remind you that what we have seen of Harry so far in the story was intended to resemble the persona of an 18-year-old Eliezer. Whatever Harry has done so far that you would consider to be "Beyond The Impossible", take measure of Eliezer's own life before and after a particular critical event. I would suggest that everything Harry has wrought until this moment has been the work of a child with no greater goal--and that, whatever supporting beams of the setting you feel are currently impervious to being knocked down, well, they haven't even had a motivated rationalist give them even a moment of attention, yet.

I mean, it's not like Harry can't extract a perfect copy of Hermione's material information-theoretic mass (both body and mind) using a combination of a fully-dissected time-turner, a pensieve containing complete braindumps of everyone else she's ever interacted with, a computer cluster manipulating the mirror of Erised into flipping through alternate timelines to explore Hermione's reactions to various hypotheticals, or various other devices strewn about the HP continuum. He might end up with a new baby Hermione (who has Hermione's utility function and memories) who he has to raise into being Hermione again, but just because something doesn't instantly restore her, doesn't mean it isn't worth doing. Or he might end up with a "real" copy of Hermione running in his head, which he'll then allow to manifest as a parallel-alter, using illusion charms along with the same mental hardware he uses for occlumency.

In fact, he could have probably done either of those things before, completely lacking in the motivation he has now. With it? I have no idea what will happen. A narrative Singularity-event, one might say.

While I'm putting it at over 90% that Hermione will be resurrected somehow, someway, it doesn't need to be in his first year.