I asked on the BS forum if the outfits were 7 day expirations (which seemed like it since they were event items) and someone confirmed that they do not have an expiration date. Holy cow! 😯 For those curious I found on the Japanese BS Wiki the images of the outfits:

As you can see the female and male outfits. They come with gloves, top, bottom, shoes, bagpack and a skull mask. The mask is facking hideous so I won’t waste my time trying to get it. Additionally to the outfits you can also get skins for your weapon:

You can turn your weapon either into a pumpkin sword or a broom. I like the broom myself…the pumpkins look like you’re about to have a pumpkin shishkabob 😆 You need 200 pieces of pumpkin candy PER PIECE of outfit. This event will end on November 11th. I’ll try to organize the dungeon runs daily if I can but remember the limit is 6 people so first come first serve sorry ><;. Hopefully when I hit 25 and make a guild it’ll be easier to organize these kind of parties (and you guys will stop getting guild spam invites lol.)