I missed Halloween and Christmas holiday events before, and did not obtain any holiday build items before.
Will Halloween and Christmas build items appear again in the future if I missed those events before?
I heard that these holiday items will appear again in the game once the calender system is fully updated. Is it true?
For triggering a Trick or Treat/Halloween event, you can place a Candy Busket on your property (anytime):
It will allow you to get/unlock all build items even if you didn’t before (tested as missed as well). But the catch is that to unlock ALL the items, you need special candies (if I’m not mistaken), which, at the moment, could be purchased only during the festival on Friday in the fall (for Dowon, they are in Central Park):
Suppose, for Christmas, it works similarly 
I unlocked most of the winter decorations during the event but on all new saves they don’t show up at all. It was finally Christmas in my new save today and I was hoping to have the decorations unlock either from the event or buy boxes to unlock them piece by piece from the booths/stalls but couldn’t. I got everything the vendors sold but it didn’t unlock anything. It’s weird because when I edit the streets, the winter decorations show up in the catalog but disappear when I’m editing my home.
Same for me. I unlock all winter decoration but they didn’t appear on a new game
