Good chapter, personaly I liked you not including the Lily and Snape friendship, it never worked for me. At most I see Snape as a creepy stalker or hanger on - bit like a Slytherin version of Wormtail.
I look forward to seeing what happens with the teachers as well, seen things like this happen a number of times but so far I have realy enjoyed the way you have reworked these kinda ideas before.
Torg.