1. Dementors don't target specific people; their goal is to suck the joy from a wizard or witch, which makes it easier to gain access to their souls (ultimate goal).
2. He hadn't seen Sirius for 12 years; as far as he was concerned, until he knew Pettigrew was alive, Black was guilty.
3. Harry's Patronus; were you paying ANY attention?
Next round:
1. I wouldn't necessarily define Black as good; against Voldemort, yes, but no saint.
2. If you've read the books, you'd realise that Hagrid is a bigger soak than Dumbledore.
3. Follows the pattern of the other films; 1 match per film.
Any questions?