My main person people for you would be Meserimus Valenduris - who is the Slytherin HoH and potions prof, he isn't much for quidditch but is a grandad type to pretty much everyone

I also have Cadawalader Selwyn - he was a talented flyer, got the captaincy of the house team -BUT THEN - the quidditch world cup incident happened, beaters were kicked off the house teams and he lost his spot on the team and his captaincy. He is however DESPERATE for adult approval even that of an MC muggleborn.

He would know Ginevra Blackwood - she is a social butterfly whose family sponsor the worst team in the quidditch league each year and hosts parties for the quidditchy people. He probably received some sort of gift or help from them after his injury, and her father would definitely have provided support for his position at Hogwarts, or tried to talk him into coaching a team. They are UCPB but generally very nice and good fun.

Yuri Podsnapper - He's been trying to get on the quidditch team for years, he's attended every practice and covered for some other Hufflepuff house members when they were sick this year. He FINALLY made the full team in the last few months and is very keen. He is a bastard orphan who was taken in by a man he tried to rob, but he was also a stone child, so is also 15 years older than his stated age.