Suho + Lexi
She probably wouldn't "hunt" him down and she can take a no very well, which means a confused look or trying to avoid her. Though flirting just happen when she interacts with people, but nothing pushy so there wouldn't be a necessity for him to be upset over it, although she is quite childish and annoying sometimes, usually when it comes to her nerd stuff, video games, board game, LARPing and she might try to get him into one of those things.
If he's not bothered by silence when with someone else then they'll get along just fine, as she just does her thing while others are doing theirs, might awkwardly stare out of curiosity though. I can't promise she won't. But it would be all good. She probably won't mind how he relates to people, she's used to that and might even make her be extra-friendly towards him.
Suho + Aspen
I can see some rivalry between the two, especially since Aspen is dating the Sturt's Quidditch Team Captain, @Lisa Knotley that's bond to create some friction between people, but at least she won't call him by his last name, which she does often.
As a Bourke she will taunt him in the field and off but mostly because he's from another team and therefore deserves to be taunted because of it. Her anger is slowly getting under control but I can't promise she won't lash out at anyone, she tries not to considering how she could be seen since she's the team's Captain. She's overall friendly, and him being as he is I doubt there would be an issue between the two.
Suho + Colette
These two can either go well or not 😂 it's only a matter to have them interact with one another.
She would spend more time rolling her eyes at him than probably make a snarky comment but she might also try to draw a response out of him, and even smile back at him as she does that. She does understand the struggles of being a halfbreed, she was after all in a school that didn't allow them, so her parents had to lie to get her and her sister in that school, she understand what's it like to somewhat be 'hidden'.
In public she's mean to her sister, @Gwendoline Auclair, calling her Dumpster Baby, and without a doubt she will punch her sister in the face for a five days old slice of pizza , but behind closed doors she's soft around Gwen and one needs to be really good friend's with her to witness such thing, so she understand what's it like being mean to siblings, she certainly would enjoy their reactions. But if anyone does anything bad to Gwen she'd literally bring them hell.
If you want we can try them out. I don't have any opens with them, just with Max but I can make a thread to see how they get along. Just tell me who you want, and we can discuss the others later 😄