The Daily Prophet was unlocked for the first time in 2014 for the Quidditch World Cup.
Griffindore House Quidditch Team
There is only one Seeker on a Quidditch team.
The Bulgarian National Quidditch team
I would defiantly check out Pottermore by J.K Rowling, which is the books turned into a virtual world. When you join you get sorted into a house and get your own wand and other awesome things. I'm pretty sure that you can do quidditch in there. Only problem is that Pottermore is currently in beta and only the beta users can use it. There's no official date for when Pottermore will be open to the public Hope that helped.
Harry plays Quidditch for Gryffindor, which is one of the Hogwarts houses.
He is the seeker on the Griffyindor quidditch team.
Yes. The Firebolt Supreme was used in the 2014 Quidditch World Cup by the Bulgarian Team. J.K. Rowling, writing as Rita Skeeter, reported on this on Pottermore.
The Chudley Cannons!
The Holyhead Harpies.