Yeah I saw the US deluxe ed. and thought "wow". That would be cool if it was Norbert, tying that in from the first book. I'm so bad with theories. However this idea popped in my head last night while trying to sleep:
I don't think Snape is evil only for this reason (because God knows I want to hate him):
The titles of the book. They are all objects or people that are used or percieved as evil are never themselves
actually evil.
The Sorcerer's Stone: Object for good intentions, the stone itself is not evil only wanted for evil doings.
The Chamber of Secrets: An open chamber
used to harbor evil, but the chamber itself can't be evil being in Hogwarts.
The Prisoner of Azkaban: Obviously everyone thinks Sirius is evil when he's not.
The Goblet of Fire: What is representative of the (relatively) harmless game, is used by Voldy as a portkey, but again the object itself not evil.
The Order of the Phoenix: The ministry wishes to say those with Dumbledore are trying to bring the ministry down, but they're in fact the good ones.
Whick brings me to HBP...Snape must be good and only appears to be on the wrong side.....
I dunno, I may be totally wrong, but that's just what hit me last night.