You about had me crying several times during this chapter. I'm so glad Harry was able to save Selene. She's sweet and it would have been a horrid loss for the whole family if she had died. Nice touch making the healer McGonagall's son as well. Her conversation with Algie about the students' detentions was interesting; I liked his take on it.
I also like what you're doing with Draco and adjusting his attitudes a bit. I love Remus and the way you had Luna be the pebble that started the avalanche of freeing Sirius and catching Peter. Awesome. I also like that Neville is friendly with the kids.