Great story I see it has not been updated in around 6 months though...I do hope it is not abandoned.
I also wonder what happened to Ron's cat, it seems that he can "see" animanguses and I think I remember something about cruckshanks (sorry SP) treating some other animal the same way he treated Peter. I wonder if there might be another person living as an animal for some reason.
I must admit that I do not like the way the Slytherins are getting away with everything. Why is there not any "payback"...They have tried to kill Harry and Ginny, they have tried to do real harm to the Gryffindor Six, they have killed one student and where holding one "hostage"! In the real world police and the prosecutors can press charges and make investigations when the people involved do not want to especially when attempted murder of a public hero is involved or a possible murder of a child. I think that this Harry would do something because he KNOWS that some of them will become DEs and he would not risk them killing someone else he likes.
Also I did find one typo in your writing...would you like to to find it again? It was in chapter 37.