This is Gawain, who's offering to tutor. He's the seventh year hufflepuff prefect. He's going to be an auror one day you know? He's very nice and polite and always willing to stick up for the little guy. Also he spends almost all his time either in the library, on rounds, or at the quidditch pitch.
Marlene McKinnon is a sixth year slytherin pureblood. She's got a front going on as a purist right now but her family is going to face a fall from grace soon so she's actually not one. But she is a bitch so watch out.
Li Shen is a 5th year gryffindor. She's a complete sweetheart and has a thing for ghosts. She wanders around the castle a lot and is very nice.
Walter Morris is the Astronomy professor and expects respect in his class towards himself and others. So depending on the kind of student he is will influence how Morris thinks of him.
And my last is Moody. I doubt he'll really be on Moody's radar though.