Hi Jules! We played together at Be Well.. :D This is Holly! I'm the other mod-ish person. I commented to your other intro but eh whatevs.
George doesn't like Zach, especially if he feels he's getting too friendly with Alicia. Not that he doesn't trust her, because he does, but he's a Weasley and is therefore short-tempered and a little ridiculous when it comes to being protective of his girl. :P
Cho also played against him in school, and she obvs dated Cedric and was friendly with Tasmin, so she'll have been polite to him at least, though she probably wasn't too fond of the arrogance thing. She's just too nice to really do much about it except not really be in the same place at the same time.