Thanks! And yes, perhaps Harry should have known, but I think it's entirely possible that he believes what people tell him too much; he doesn't go looking for lies (unless he already has reason to be suspicious of someone, the way he does of Draco).

Should this be Hermione Granger-Weasley or is this a different custom you know of? Sorry, I know it's picky but it grabbed my attention.

Weasley's first because, in this story, they're very clannish, and I can imagine Hermione wanting to keep her last name but being willing to compromise on where she put it for the sake of peace.