Just another thought on Lockhart -- he really did, after all, do all that exotic travelling and meet up with all those dodgy characters. He just took credit for other people's stories. So he's really, mabye, more of an obsessive fabricator than a plain coward. But I like your idea that he obsessively identifies with the virtue of courage, even if he can't quite live up to it. And he does have the Gryffindor trait of setting a goal and going for it, damn the consequences! Though perhaps that is a Slytherin trait as well.

I like your point about variations within House types. I heard about that meme you cited, about people being a combination of house traits, and I've often wondered about this within our fab foursome: we clearly have met four different types of Gryffindor that reflect a kind of cross-product with other houses, Neville being a Hufflepuff!Gryffindor, Herminoe a Ravenclaw!Griffindor, Ron a Gryffindor!Gryffindor, and Harry a Slytherin!Gryffindor.

I think we're both frustrated at the lack of attention to characters from other houses, to sort of flesh out the typology. But Draco is probably a Gryffindor!Slytherin (I do give him credit for resilience and boldness, if not exactly courage). What is Snape, then? Perhaps also a Gryffindor!Slytherin due to his dangerous double-agent role and his desire to teach DADA -- or perhaps he only aspires to Gryffindorhood and is more of a Ravenclaw!Slytherin engaged intellectual at heart. Dom!Ernie has something Gryffindorish about his Hufflepuffness, while skeptical Zach seems more tinted with Ravenclaw critical thinking. And then we could add positive and negative aspects to each variable . . . Hmmm, hours of fun. Or not! :p