If this event will be unique and not something with aliens, and looking at what has already been done, I'm gonna guess it's gonna be one of three possibilities:
- "The Island of Dr Hibbert" with animal versions/skins of characters, maybe even getting to turn them into these with something similar to the zombie sandwich
- "Attack of the 50-foot Eyesores" with either getting to build those mascut statues and them coming to life later on or them being big characters like Gelatinous Homer and maybe rampaging around like Wiggops or the Trolls
- "War and Pieces" with buildings based on the evil board games on that game, maybe with being able to pop the evil card monsters from the episode
An event based on Send in the Clones or The Others is unlikely since we just had an event with Homer clones. As for individual, not directly event based characters, maybe Homerzilla, Lisa with Barts head, the Fat in the Hat and Hitman Homer and Marge could be possibilities. I would also love to see something to do with Nightmare Cafeteria, but I'm not sure how that would work.