It's so nice that Ukraine have so many various traditions, i think! In Australia, we don't have a lot of cultural traditions so we mostly just celebrate the big dates that are known worldwide, like Easter, and Christmas.
That's great to know that there are parties enough for Halloween celebrations, though! :) I think the adults have Halloween-themed parties here, as well, so they can get to dress up, but there's not very many kids who does trick-or-treat from door to door in Australia
Good luck with finding costume! :D