I know you asked this ages ago, but I just saw this thread.
We went pre-Covid and we were there for a week, leaving on October 28th. There was a Halloween party with costumes, treat bags and festivities on a few dates leading up to Halloween. They also offered things like pumpkin carving on different dates.
Hope something falls on when you are there. We had a lot of fun!
We were there for Halloween pre Covid and it was fun. The characters were in their costumes, they had trick or treat around the valley and the show was also fun.
However I will say. We decided it wasn’t a must do because our kids like being home and scaring the trick or treaters more than the shows and characters.
Pre-covid most of the activities started a few days before Halloween day such as pumpkin carving contests, pumpkin decorating and Disney Halloween movies for Ohana Movie Nights. On Halloween they've had a dance party and trick-or-treating as well as Disney Characters dressed in their Halloween attire. I don't believe most of these activities have occurred in the past two years.
I don’t know for sure because we arrived 2 days before and it was very Halloweeny? But I will say that on Nov 1. It went back to beach cloths for all the characters and no more pumpkins out. The switch was very quick.