Crystal and
Celia - These two are in the same year, and I'd love to throw them together, if only because Celia wants to ask Crystal why the hell she decided to come back to HNZ
Anyway, Celia can be pretty abrasive/judgmental, so I'm not sure how well they'd get along. (She would think the obsession with magical creatures to be pretty weird). She wouldn't go out of her way to bully someone who hasn't wronged her in some way, but she could definitely be someone who sees through Crystal, if you want.
Crystal and
Weston - Weston Stirling is my seventh year Ravenclaw, who wants to be friends with everyone. He also likes magical creatures (from a safe distance), the more dangerous the better, so they could definitely bond over that. He'd love to hear all about dragons from her.
Christina and
Harper - Back when they were in school, I kept on meaning to reach out to plot since I always thought they'd make good friends. Anyway, Harper's a year younger and is also a former Gryffindor who loves sports. She's fairly easy-going and gets along with most people. Harper's currently based in New Zealand, but she'll be traveling a lot in 2059 so they could run into each other in England if you want.
Giselle and
Harper - I'm throwing this one in here because Harper's a bartender (at a muggle bar). They were in the same year, and Harper would be happy to talk to Giselle if she ever showed up at her bar.