Hi! Welcome! I'm Lyddia, the other half of the mod team, and I probably have... Uh like 10 characters? I don't remember.
Like Alissa I have three in the same age group as Hiro! They are... Aaron (this journal), Presley (tootsie_pops), and Toby (iamthelegacy). Aaron is best friends with Wes and Jack's sister Annie and he also sells drugs to Elliot. He's that kid who can get pretty much anything you ask for--legal or illegal--and he tends to hang around the crowd of people who follow Corporate Lobotomy. He has a power, but no one is supposed to know about it. He didn't grow up on the island, but he's a special circumstance... Long story!
Presley is Elliot's (best?) friend. They share a love for fashion and make their own clothes. They might have some awkwardness soon over Jack because they're both kind of in love with him. Presley grew up on the island, which means she has a power (mediumship). She went to Wyrd Haven Academy, but her power is pretty easy to adjust to, so she transferred into JFKHS where the non-powered kids all seem to be.
Toby is also from the island! His power is agrogenesis. His best friend's are Jack as well as Dale Allen. He goes to JFKHS, but attends Wyrd Haven for power control classes, so they'll probably know each other from that! Up until this semester though, he was enrolled in yeshiva with other Orthodox Jewish kids. After his mother died (on the last day of Hanukkah!) his dad decided he'd be better off attending school with his friends (and also his girlfriend Sarah, who he's sort of head over heels for). He's also the new bassist for Corporate Lobotomy!
Uh, also, I've got the new headmaster's best friend David Bacchus. He'll be the theater teacher at Wyrd Haven at the beginning of the next school year, but sometimes he shows up to talk about being a mutant as an adult and dealing with your powers or something... I dunno.
I think those are all the characters Hiro would know, for the time being! I look forward to having you around!