Idea: the Curtis brothers are Harry's mom's cousin's kids. Harry goes to live with them after fourth year. They don't know that he is a wizard till his letter comes. Middle of fifth year the toad gets seven books on Harry. 4 past and 3 what could have been. The toad decides to read them to the school to try and prove that harry is a liar.
People the toad brings in (3 people)
People Professor Dumbledore brings in
Sirius (as padfoot)
Dallas "dally' Winston