1. Alastor
2. Tom Marvolo Riddle
3. Barty Crouch's sacked house elf
4. A group lead by Harry Potter that learns Defence Against the Dark Arts
5. Half brother of Hagrid
6. Albus Dumbledore's phoenix
7. Moaning Myrtle is a ghost that was murdered by Tom Marvolo Riddle (a.k.a voldemort)
8. Moony, Wormtail, Padfoot and Prongs are Remus Lupin, Peter Pettigrew, Sirius Black, and James Potter.
9. Professor Grubbly-Plank is the substitute Care of Magical Creatures teacher.
10. People can't see Thestrals because they have not witnessed death at least once.