Hello! I'm Ally, welcome to the game! I play lots of characters and I think some of them definitely will know Miles :)
Terence Higgs (this journal): He's currently working as a Hitwizard, recently having returned from 10 years in the Muggle army. He would have spent a few years on the Slytherin Quidditch team with Miles, so obviously he'd know who Miles is. Higgs is also like the world's nicest Slytherin and is married to Alicia Spinnet. Going-out-for-drinks kind of friends?
Oliver Wood (quidditchary): Plays for Puddlemere and obviously would know Miles because Quidditch. Oliver's pretty friendly so he'd be happy to be nice to Miles if Miles was nice to him!
Jun Dorney (jdrny): She's a painter and would've been two years above Miles in Slytherin, so they might know each other?
Aisling Astor (aastor): Plays violing for Quake, so he might know who she is because of that but I can't really see how else she'd know him?
Zac Smith (zsmth): He's an investment banker and as one is an absolute asshole. He says he neither cares not wants to be friends with Miles. This is not shocking.
Evan Potter (potterlings): The younger brother of Harry Potter. He's studying magical architecture at Cambridge Uni. He has no reason to know Miles, alas.