Holden is the shyest jock who ever jocked, and is probably super intimidated by her, but he is the easiest to boss around because he likes causing as little a problem as possible. Probably not too much there, since he's younger and in a different house.

BUT, she might know more about Sylla here! She's a former Slytherin a year younger than Iris, and her family has a bit of a reputation for being weird and shady (Borgin & Burke are her parents :p), and also for the seven other Borgin girls who all clung together pretty close at Hogwarts. But now Sylla is looking to branch out and be around people who don't know her from the family's nefarious past, and they'd be in animagus studies (well, when Sylla creeps in on the senior class, that is). But I'm sure enough of that has crossed the pond also!