I was so glad that the house-elf stuff got cut out of the movie #4.

I think the thing with the names is that everyone stays within their own house, and only really associates with their house, except in places like the Quidditch field and potions. There's a brillant idea - let's take these two groups of kids that we encourage tremendous rivalry in, and then stick them together in a class where they could concievably poison each other.

DV