Ravenclaw: Aida Riko (hardcore fan and helper), Momoi Satsuki (hardcore fan and helper), Mibuchi Reo (Chaser), Midorima Shintarou (Chaser)
Hufflepuff: Kiyoshi Teppei (Captain and Keeper), Hyuuga Junpei (Chaser)
General Headcanons
Aomine and Kise are childhood friends. When the Sorting Hat divides them in two different Houses, Kise throws a tantrum about it, but Aomine manages to calm him down and persuade him this is even better: both friends and rival at the same time. They still spend a lot of time together, breaking down walls of prejudices between Houses just by being friends.
Aomine is also very close to Kuroko and Kagami thanks to their love for Quidditch and soon they become a noisy quartet. Kagami and Aomine spend their time bickering for who’s the best Chaser and who’s gonna be the captain in the future, but when they play they synchronize perfectly.
Kagami and Aomine also like to bet and challenge each other continuously about everything. The crazier, the better. They continuously lose points for trying illegal things and spend more time in the McConaghall’s office than in classroom.
The thing no one knows, it’s that is Kuroko who provokes them but he always disappears when trouble arises.
Kise and Takao are besties, they are the bubbling and teasing duo of Slytherin. On the surface, they seem in the wrong House, but when they get mad or feel challenged…well, the Sorting Hat was more than right.
Kuroko is the only one of them awake during History of Magic and asks sweets as payment for the notes.
Nijimura and Kasamatsu are best friends, fighting to discipline their flaming juniors, who, behind their backs, call them Mom and Dad. Sometimes, they even holds Group Study Sessions to help their stupidest players to pass the exams.
Kasamatsu is totally unable to talk with girls, becoming a blushing and stuttering mess, and this is a problem since Nijimura is hell popular; the girls pity him so they try to not pressure him and Nijimura try always to calm down his fanclub before Kasamatsu stops breathing.
Gryffindor Mom and Dad at first loved Kuroko the most because he wass the only one who seemed normal and didn’t cause disasters every five minutes. Then they realized that half of the time he was the cause of the disasters and remained purely shocked.
Haizaki and Kise hate each other to the point sometimes the first one tries to hit the other with the burdgler and the second use the Quaffle as an improper weapon. Only the Captain can keep the two of them separated and make them cooperate (partially).
Actually, the major duty of Imayoshi is to avoid his players kill each other. They’re the Ticking Bomb Team. Takao and Kise can’t stand Haizaki, who hates them too, and Mayuzumi hates everyone, causing rucks even if he’s older and should help out instead. He especially despises Haizaki and Kise. Himuro tries to calm them down usually, but he’s not enough mature and usually ends up taking sides with Takao and Kise. Murasakibara sleeps or threatens to crush them all. Akashi doesn’t take part in their stupid bickering until they become annoying or they drag him in: this makes everything stop because they’re all secretly terrified by him. Let’s be honest: Akashi is Imayoshi’s secret ultimate weapon.
The only thing that keeps the Ticking Bomb Team together is their pride and burning desire to win, so they’re really scary during matches.
Mayuzumi’s personality reveals its true nature only when he’s playing. He starts to swear aloud and threatening verbally the opponents, cursing under his breath and swinging his bat as he’s ready to behead someone.
Himuro is one of the most appreciated guys by the Hogwarts girls.
Akashi and Kuroko have that typical cold and polite rivalry, full of smile and hidden messages that makes the air chilly and sends shivers down the spine of all the presents.
Himuro and Akashi are close friends.
Aomine is very protective towards Kise, even because there are few Slytherin guys he likes (practically only Kise’s closest friends). He has warned Haizaki more than once to keep his hands off him. So Haizaki always targets him during matches.
Akashi and Midorima are library buddies at first and then they become close friends. Akashi always searches for his help when he has Muggle Studies’ tests.
Riko, Kiyoshi and Hyuuga are childhood friends and still very close to each other. Since Kiyoshi’s mother is a witch, he helped them a lot when their letters came and their families freaked out.
Here, I imagine Momoi being the same age as Riko, with them being like sisters, and a close friend of Mibuchi.
Hyuuga is so scared of phantoms he freezes every time one of them tries to speak with him. Even in his last year. So all the phantoms pity him and try to not appear suddenly by his side.
Hyuuga is scared by Kuroko too, for this reason, and he hates playing against him.
Kiyoshi is a sort of Mom of the school. All the other younger and desperate captains go to him for suggestions to manage the teams. Actually, he had instituted the Captains Reunion once a month to speak with each other and exchange suggestion, opinions or even only just to complain about their teams.