Review of chapter 7:
very nice. If I was in Harry's place I'd have tried some other tactics to evade the Headmasters manipulations before showing up in Hogwarts or at least make it more uncomfortable for him when I do show up. However Harr's not me and your characterization is consistent.
I liked the description of events on the train, especially the Hermionie and Harry's thoughts about her (I really liked your explanation for how and she ended up in Gryfindor). so far you're doing a very good job of not changing things which have no reason to change, nor forcing events into the template of the books (the two most common mistakes with AU stories).
One nitpick - why didn't Hermionie ask about Harry's book?
The Unicorn