I can't complete this game! I've got every character token from every level, every hat, every red brick, won every duel in duelling club yet I only have 98.4% completion and there are 4 characters still locked (3 between Griphook and Hagrid and 1 between Petunia and Professor Binns)! What am I missing? Please help someone!
I had the same problem. It turns out that I missed one of the multi-character tokens. It sounds like you missed the same one I had missed. The token you are looking for is in year 5 chapter 4 hall of prophecy.
Here are Multi-Character Tokens locations:
1) Year 5, Chapter 4, Hall of Prophecy: destroy the small bone pile on the left inside the arena.
2) Year 6, Chapter 4, 3rd area (with the goblets): destroy the small bone pile in the central area.
3) Year 7, Part 1, Chapter 1, The Wedding: Use Spectrespecs behind the ice statue, then use the gold ring to reach a little room, then blow up the presents.
4) Year 7, Part 2, Chapter 3, The Battlements: Destroy a small bone pile on the ground.
All credit for this list goes to TGSnowwy