His being friends w/ Kris ensures that Cash will almost certainly try to avoid him and be mild->moderately disdainful when they do interact.

He definitely didn't get along with Zelda Darrow, who was a year mate. Noble Greengrass was also a year mate but isn't a purist so I doubt they vibed.

Effie Faraday is a halfblood but has informed me she'd be willing to flirt with him?