Do you think the boys celebrate Halloween? If so, who dresses up like what (if they dress up at all) and what can you picture them doing this holiday?
I bet the only ones who really celebrates Halloween are the obvious - JJ and Leo. Keep in mind all the boys are from other countries where Halloween isn't widely celebrated. Switzerland, China, Kazakhstan... they don't have Halloween the way we do. I mean, western Halloween is kind of slipping into the youth culture of these countries, but not in huge significant ways.
Yuri spent so many years in America that I'm sure he's aware of American Halloween traditions and is probably pretty fond of them (I can imagine him absolutely loving the concept Halloween candy; I bet he likes candy corn), and while in America he probably did get invites to little Halloween gatherings as we know them, but in Japan, Halloween is purely an 'adult' holiday - mostly an excuse for people to dress up and get rowdy at parties and bars. He's definitely not the kind of person to go out like this xD We saw what happens when he's drunk. I doubt he actively seeks out these situations.
Far, far fewer people celebrate Halloween in Russia. Russians are aware of the holiday, but there's a lot of controversy surrounding it. I really don't see Viktor to be the kind of person who'd do anything that the people of Russia who adore him would frown upon. He also doesn't strike me as the kind of person to just go out drinking at clubs. As for Yuri, I'm sure he's dying to celebrate Halloween (because in Russia it's almost a punk/rebellious holiday,) but since he's still so young, he really can't get into any of the bars or clubs where young adults go to celebrate it. I know the drinking age in Russia is pretty loosely enforced, and I assume the age restriction for getting into clubs/bars isn't really strictly enforced either, so maybe now that he's 16 he can start trying to sneak into some of that stuff hahaha
Halloween is pretty controversial in Thailand, too, from what I understand, and it's only really celebrated in big cities with foreigners, like Bangkok. But I imagine Phichit went crazy for Halloween while in the US, and he's totally the kind of person to get all dressed up and head to some of those parties back at home. He probably carves pumpkins and puts up decorations all while his family and friends shake their heads and hope the spirits don't come after him xD
And I'm sure Otabek knows some club hosting some kind of Halloween party that he'd go to. He doesn't seem like the type to dress up at all, but I think maybe he'd do something simple like put on fangs or maybe some fake blood on his face or something and then just wear his normal clothes. I know they don't celebrate Halloween there, but he probably knows some kind of bar or club with a costume themed night for the occasion.
That's about the most I can imagine. Chris definitely wouldn't celebrate, Guang-hong wouldn't, I highly doubt Seung Gil would. I guess maybe the Italian siblings would since it's getting more popular over there? Eh. That's about it.