Ezekiel D'Vaccaro, I COME BEARING GIFTS.
Gemma Odair is my pro quidditch player, beater and captain of the Caerphilly Catapults, best friends with Zeke's captain, and mortal enemies with one of his other teammates. I'm sure that the two have seen each other around at the very least, and I get the feeling that they'd either get along swimmingly or have a sort of acerbic rivalry depending on how at odds their senses of humor turned out to be and whether or not one of them has recently tried to knock the other out of the sky.
I also have her brother, Isaac Odair, entrepreneur and, more importantly, bar owner. If Zeke's got any reason to drop by bars in Knockturn, he may have stopped by the Cat and Mouse. He's got the same sort of wit as his sister, and generally a less aggressive attitude.
If you're looking for someone closer to Zeke's age, I also have Ryan Villein, a halfblood who thinks he's a pureblood. Not sure what we could do with them, but the fact that their lineages are opposites of each other is funny to me and if you want to try and sort something out, I'm game.
Anyway, let me know what you think!