I am way more massively late on this than Brandi :/.
OKAY SO, James and Mary, I'm thinking, are buds. They've already interacted on the journals, and I'm thinking we have the basis for a good old sarcastic, joking kind of friendship, but James would definitely get on well with Mary! They've known each other for a loooong time, and the fact that they played Quidditch together really seals the deal. An interest in Quidditch is a sure, quick way to make friends with James.
Evan probably hates her. Would have backed Mulciber 100% in whatever nasty thing he did to her in fourth year xD. He probably thought it was pretty Bad Ass.
Ernie likely wouldn't know her, but he would be nice :D!