The fic does cover their Sorting, a little of their Hogwarts years, and then they're working as Aurors. The fact that they're Slytherins is important to both of them within the fic.
I don't necessarily disagree with you, in terms of ease of AU writing? Like I said, most of the time I give these arguments in the context of random Sorting conversations. Castiel a Gryffindor? Nope, Castiel's a monster in the forbidden forest. NEXT. Ovi's in Slytherin? Ovi wouldn't even go to Hogwarts. NEXT.
I do think you could easily write a Hogwarts AU or post-Hogwarts AU without sorting non-U.K. characters into Hogwarts houses, if you really wanted. The Goblet of Fire has students and professors visiting from different wizarding schools. You could have wizards moving to the U.K. and working as Aurors, since I don't recall anything about that being against the rules in the wizarding world. I'm not saying that's what everyone should be doing, since I think people write these things to replicate Hogwarts and the things they liked about Hogwarts, but it is a possibility.
Re: Fic Discussion - aparecium by oops_ohdear
The fic does cover their Sorting, a little of their Hogwarts years, and then they're working as Aurors. The fact that they're Slytherins is important to both of them within the fic.
I don't necessarily disagree with you, in terms of ease of AU writing? Like I said, most of the time I give these arguments in the context of random Sorting conversations. Castiel a Gryffindor? Nope, Castiel's a monster in the forbidden forest. NEXT. Ovi's in Slytherin? Ovi wouldn't even go to Hogwarts. NEXT.
I do think you could easily write a Hogwarts AU or post-Hogwarts AU without sorting non-U.K. characters into Hogwarts houses, if you really wanted. The Goblet of Fire has students and professors visiting from different wizarding schools. You could have wizards moving to the U.K. and working as Aurors, since I don't recall anything about that being against the rules in the wizarding world. I'm not saying that's what everyone should be doing, since I think people write these things to replicate Hogwarts and the things they liked about Hogwarts, but it is a possibility.