I feel so bad for what happened to most of the witches and wizards. Could Harry come up with a way to bring witches and wizards back together again? Maybe teach them spells while he never finished his education DA should have taught him that he is a great teacher. All he needs is wands. Could he some how find a way to get into Gringotts. Have them give Harry all the wands stored in vaults. And maybe make an agreement with the Goblins to come out of there self imposed exile. Some of that gold could be used to create a new school. Harry could teach when he can. And his students when they get good enough can teach other witches and wizards.
Author's response
That was the general idea. I'm glad I was able to elicit the emotions dealing with the loss of the knowledge that the wizarding world had.
Now I can't comment on your other thoughts as I would give away the plot, but keep on reading and reviewing.