Yay, welcome to the game! I'm Patricia and I'm the mod here, so if you ever have any question or need anything, don't hesitate to ask. :)
I have five kids here, some of whom Henry will know in one way or another:
Firstly, there's Cormac McLaggen (myownfanclub), fifth year Gryffindor. He's loud, childish, immature, obsessed with girls, Quidditch and his own awesome self (well, awesome in his own eyes, that is), but underneath all his braggart ways he's just an old softie. He's trying to rebel from his purist family but is failing terribly at it so far.
Then there's Hamish Fraser (notahamster), sixth year Ravenclaw and the Keeper for his house's team, so Henry will know him from playing against him. He's a thick-accented, gruff-speaking, kilt-wearing Scot who, in spite of appearances, is actually very sweet and girl-shy. He's the identical twin of Cassius Warrington from Slytherin (they were separated at birth by their purist grandparents and only met at Hogwarts) but it's not hard to tell them apart since they actually prefer to accentuate their differences.
There's also Samir Karim (littlepharaoh), sixth year Hufflepuff. He's a muggle-born from the posh part of London, but he's not stuck-up in the least. He's now living with his friend Barney's family, as his parents kicked him out after he came out, but he's trying to fight any negative feelings about it by putting all his energy in all the artistically-inclined clubs (besides being housemates, Henry will be in Book Club with him) and by mothering his friends and housemates. He's very loud and hyper and likes to write in CAPITAL LETTERS when he's excited, which some people find a little intimidating. Also, since Cedric is one of his best friends he'll be Team Diggory all the way, but he'll still be nice to the other champions and their supporters in his loud, inimitable way.
There's Zoe Wagtail (this journal), fifth year Hufflepuff prefect. She's the baby sister of Myron Wagtail (lead singer of the Weird Sisters), but unlike her brother she's responsible and no-nonsense. She looks and acts cute and sweet, but cross her at her own peril. Hers is a fiery temper, and it's only her attachment to her shiny new badge that stops her from following the Alastor Moody School of Punishment - that, and not knowing how to turn humans into ferrets yet. Because of this, sometimes she'll stick to mocking them mercilessly instead.
And finally, there's Tiago Delgado (lj user="surfistinha">), seventh year Beauxbatons student who hails from Portugal. He's friendly, sweet, nice, and someone you can always count on to see things from a calmer perspective. He's a bit of a jock, as he not only plays Seeker in one of Beauxbatons' Quidditch teams, but also enjoys surfing and playing football with his muggle friends back home. He's also a known pot smoker (though he was never caught red handed), which might explain his calmness at times.