I have three here - Ethan Proudfoot, Lennox Campbell and Tabitha Ogletree.
Ethan will probably have most to do with Charlie, as he's Deputy Head of Flying Creatures. He's a pretty chilled out guy, outdoorsy himself (played Quidditch at Olympus) and while like his siblings in terms of intelligence, he's definitely one of the least intense. He's also involved in the dragon plot later in the month :)
Tabitha is only 18 and a herbology intern, so they'll probably just cross paths as randoms.
Lennox isn't the one from Neep and other games - he's that one's much more outgoing nephew! They should talk Quidditch sometime as they have the Gryffindor Seeker thing in common, although now Lennox is Seeker for the Kappas and does a lot of charity work, which is how he ended up on the board at Brightstar. :)