I'll hafta reread you fic, Cass, because I must've missed it.
In my fanfic, though it's never mentioned, my version of Sirius' mother, Evelyn has Irish in her, too. How strange.
Actually, I guess it isn't. Even though it's kind of a stereotype, Irish people do have a rep for hot blood and I definitely see a lot of that in Sirius.
I think Hagrid is probably Cockney English--y'know, like Eliza Doolittle from "My Fair Lady".
My boyfriend thinks McGonagall is Scottish, but I think she'd be very prim and proper English.
I think Snape might be Welsh, or have Welsh in him. I only say that cuz Alan Rickman does. (I know nada about Wales.)
But yeah, I can see him as being from some English city with lots of Roman landmarks.
Dumbledore? I always imagined him talking with a high-class British accent.
I think Remus probably grew up somewhere out in the country...near the woods, where the werewolf bit him.
Sorry if this post is a little crazy, I just sat through three hours of slides of old paintings and a boring lecture at a college seminar.