FIRST! A reminder that there WAS a Friday--I mean, THURSDAY EGSNP, so if you're confused, you probably missed that.
Now, on to the actual commentary.
I felt the only way for this bit of a twist to work with Susan was for her reaction to be mild exasperation, effectively followed by "neat".
Were Susan actually uncomfortable with the situation, everything would have to come to a halt, I would owe her approximately six thousand apology fruit baskets, and Diane would probably demonstrate how many levels she has in a rogue class by punishing me in a way I would never see coming.
Side note: "Mild exasperation" felt like the right way to express what I meant, but "exasperation" apparently means "intensely annoyed", so I'd argue that "mild exasperation" is a baffling combination of words worthy of becoming exasperated about.
As for the question "do the NPCs see something different, or is this just considered how not dressed a person can be from their perspective, therefore it is of similar social equivalent", I leave to reader interpretation. Which is basically my way of saying "I'm not going to clarify it in the comic itself, therefore, it's left to head-canons".
"Head-canons" as in individual interpretation of story canon, not, like, "head-cannons", like what you might find on an android who'd decided they had some extra room on their forehead for a bit of ordnance.
EDIT - OH YE GODS I forget to say anything about Sarah and Ashley. Um... I felt Sarah should be there, but I had limited panel space, so I drew her small, and then I was like "but why small", so there's Ashley, and they both have drumstick wands, and you're just going to have to head-canon what's going on there, because that's all I'm giving you to work with on that one.