CAYLIE is a year older than him, so they would know each other from school. He's got literally the worst personality to get along with her, but she makes an effort (and it is an effort) because of Cal and Dean, and generally not wanting to be a Debbie Downer.
VIC has been with the Defenders for over ten years, so he definitely knows Matt from there. It's hard to say how much he considers Matt a teammate, cause that's not how the Defenders roll, but I can't see him having a problem with the guy. Matt's just probably not his favorite person. And he's somewhat amused that Matt can copy his ability to cast spells, but not the knowledge of the actual spells.
DEAN was a baby and toddler while Matt was little, so they had a lot of playtime together until Matt started school and Doreen moved on. He can definitely get caught up in the silliness of not taking things seriously - he used to be a lot more ridiculous and the prank-pulling type. But he doesn't like the sharper edges of Matt's personality and tries to call him on it when he goes too far into douche nation.
EVE is the one most likely to have a legitimate problem with him. I don't think they'd have much past interaction, but there's potential for them to meet up in the future, which should be interesting.
Actually, ASH would probably be really turned off by his personality, but would initially think the problem was him and try to understand Matt better. He's just such the polar opposite, naive and caring and a total pacifist who's all about coming together and living in peace. He's also a hedonist who is just now starting to learn about the vices and pleasures of the real world and needs people to be a bad influence on him. Get in while the getting's good, Matt!
ERIC and ALEX probably have the least to do with him after all that.