It is indeed one of the most memorable scenes of the entire series.

I disagree. As I've said before - and you agreed at the time - Cho seems like a cool girl who gets the short end of the stick from Rowling because of that awkward fling with Harry. All of her reactions make ample sense from her PoV, though - it's just the circumstances are so difficult that it was never really going to work.

I think you're still biased by your fan-fic. Bullying is bullying, whatever excuses they offer for them. And as Harry notes, they start to bully him because they feel bored, not for any other reason. Of course Lupin and Sirius are right that it doesn't mean they are bad people, and it certainly doesn't mean Snape is an innocent victim, but it is what it is, and it isn't pretty, alright.

I'm not really happy with that part of the scene, in the light of the later revelations. Snape's calling her a mudblood strains credulity as it is, but it's Lily's reaction that is the most baffling. Is she really that much of a sphinx that she doesn't show the slightest sign of feeling hurt other than blinking, and merely insults him right back - borrowing James' insult, too?

What is "bad"? Most bullies aren't "bad" in the sense you seem to mean it, and bully more out of boredom or to impress their friends than out of any real malice or cruelty. James is as "bad" as, say, Draco Malfoy. Fortunately, they both grow up.

Yeah. That attitude must've made his time in Azkaban all the harsher in contrast.

Agreed.

As I said above, I find her reaction strange. I suppose we never really see enough of her to know her character, know whether she is indeed capable of perfectly concealing the hurt feelings she must have. Or perhaps it's just plot convenience here - if she had displayed a more logical reaction in the light of the later revelations, those revelations wouldn't have been as surprising.

I think it has a lot to do with how the Marauders are still seeing everything as a lark and have had little reason to take things seriously, whereas Snape, like Harry, is more mature that way, forced by the circumstances. Most children do indeed do stupid things at fifteen that they are later ashamed of; Harry has been forced to be more mature, and has a hard time understanding such immaturity.

He doesn't know about the mirror. The only thing he knows is Sirius' vague description of it, but he's immediately decided not to use it and so quite naturally doesn't remember it when thinking of ways to contact Sirius.

Agreed. I don't remember now whether his getting caught the next time has to do with having left traces this time, but it might be, so that makes it even worse.