Rowling made a point out of making the Wizarding population quite small. While we see a lot of Hogwarts students in the films, that's deliberately not the case in the books. In Gryffindor, there's only five boys in Harry's year (him, Ron, Neville, Dean and Seamus) and three girls (Hermione, Lavender and Parvati). Chances are there weren't many more "face in the hall" students than the ones mentioned here and there.
However, the differentiation you're making is very interesting. I've come across quite a few people that resent Rowling's writing because of these details and miss the fact that she wasn't aiming for a sprawling epic with big family trees or a complex magic system. In fact, I'm pretty sure she has said she doesn't like fantasy (years and years ago) and that it hadn't occurred to her that Harry Potter could (or would) be considered as such. She wrote a boarding school story with magic, basically.
There's a very interesting conversation to be had about genre expectations and Harry Potter if people could just put aside the Derangement Syndrome tbh (not you, of course, just in general).