Jamie's~ Posy was there! She definitely sought out Blue's assistance in clothing, so I'm sure she was decked out in only the finest. She didn't really understand what Pride was until she was actually there, I'm guessing, and she loved it. (Kit, if you would like Neville to go, she would definitely have tried to drag him along.)
Nikolai does not miss a good party and this is one he can wholeheartedly get behind. I think he probably would have initially gone in fairly normal clothes for him, which is already a bit bright and exciting by default, but would have just progressively added to the color as the day progressed. He doesn't really have the opportunity to express and embrace his sexuality back home, so it was pretty freeing to experience for him.
Vax totally went and would have happily dragged any of his friends along, so feel free to say that he did so, if you need an excuse. He wore black. 🙃 I want to say that he ended up with some kind of bi representation by the end, though. Maybe he swapped out his beads for bi colored beads, something like that. He enjoyed it all, though, because it was like a brighter and more exciting festival from home.
Annie isn't good with crowds like that and only would have gone if Gale wanted to go for any reason. Cassandra is much the same, but would have gone if anyone else at Greyskull invited her. I want to say that Essek was there for like five minutes by accident after teleporting for Starbucks and was just a bit wide-eyed for a second, got coffee, and went home.