Hey, Megs! I think I know you. =P Obviously you have a problem, but don't we all. Keep the lovely characters coming!
You already know James, so I won't break him down into great detail. James knows the Weasleys well enough, so says he, though I'm not sure if he's heard of Lavender unless Ron's made mention of her via his journal OR to one of the Potter spawn. Then perhaps? I'm sure James would be nice enough to her because she seems like a good girl (and Parvati is dating his eldest, so there's that)!
Angelina knows Lavender from Gryffindor of course, though I'm not sure if they were incredibly close. I think there was a high likelihood Angie lurked around to catch up on all the latest gossip (it's difficult not to be curious what the rumor mill is putting out these days), but she probably was casual friendly with Lav all things considered.
That's all I can think of for now. Let me know if you have more! MUAH!