During VoldemortÆs purge of magical Europe, he attempted to claim Hogwarts as his own, but the assault failed. However, the castle was heavily damaged, and forced to close. It has only just recently been stated by the reformed School Board that it will reopen this school year, with expansions and modifications to the castle to accommodate the new influx of students, along with full faculty rosters and the addition of teacher assistants to help accommodate the new size of the student body. Hogwarts is now as much an experiment as it is a school. An attempt at organized magical instruction of this scale has never taken place before, and success or failure here will have far-reaching consequences, not just for the rebuilding society of magical Europe, but also whether or not continental Europe will decide to expend the resources and political power necessary to recreate their own magical schools.
A few thoughts.
Since Europe is so devastated by the war, would it not be possible that they may reach out to other continents for assistance? I mean if I read your post correctly, Africa, Asia, Australia, Japan, and the Americas were untouched by the magical civil war, and IÆm sure that there are talented and capable teachers that could be found amongst those lands. IÆm not saying this should be a major focus but a touch of flavoring and world building, and a chance to play around with how wizards from other nations/traditions work their magic, and teach it to the young.
Now any males from these foreign lands thatÆs brought in to help teach will be extensively vetted to make sure they donÆt intend to take advantage of the situation. I also imagine that most of the ones who are picked to teach will tend to be other men with grandchildren, or happily married.
Also since the school has been expanded and now has many more students, itÆs likely that theyÆll need a larger staff to ride herd on all these students.
Possible Examples of Hogwarts Foreign Staff:
Care for Magical Creatures-An older Rancher type from the USA Midwest or an Aussie Big game hunter (ôI capture and release thank you very much.ö)
Potions- A Mad scientist (*HarryÆs lips turned down as the goggle wearing professor swept into the room, threw up his hands and said* ôWhose ready for Potions!ö)
Transfigurations û An initially serious looking Japanese business man, turns out to be a master cosplayer of indeterminate gender that may or may not be human. (ôI donÆt knowà.those fox ears look a tad to real to meàö *teacher continues on, energetically discussing the course as his/her/itÆs three tails swish behind)
Herbology û A foregin farmer possibly from Asia or Africa
Muggle Studies û A former reporter for a reputable muggle newspaper/news organization
I also imagine that Harry wouldÆve been offered the teaching position in ôDefense against the Dark Artsö If he turns it down, then the person they got to fill the role could feel threatened to see such a knowledgeable superstar in his class, or might make Harry his unofficial TeacherÆs Assistant. If Harry accept, then he has to juggle his school load, plus prepare lessons and grade papers. Something Hermione would be all too happy to help him with.
If you were to go with Harry becoming the teachers T.A. IÆd pattern the professor after the child of a government spook, the more or less worked as that for his nations wizarding community. Harry might even know the person from the war as they provided some aid to his side.