Here’s a theme:
Carnival theme! There’s a lot of colorful items you can use. A lot of the new items coming in for fall could also work.
The carnival could have several different parts in the island.
-You have a park ( some items you can use: Elephant slide, springy ride on, swinging bench, tire toy).
-A food court with lots of stalls. There is also these items you can use: cotton candy stall, popcorn machine, frozen treat set.
-Carnival rides: race car bed as bumper carts, tea cup ride, you can also use the lifeguard chair with a small a plastic pool (kind of like a carnival dunk game). Or a lifeguard chair with screens around it (to pass it off as the tank).
-colorful wheel to spin for prizes (with a booth next to it with the prizes). You can have gold fishes as prices or doll, etc. also the toy bears.
-There’s lots of balloons from Redd to use. Also the balloons form the Easter event. The Easter furniture also look great in a carnival theme.
-A pumpkin patch from coming October update.
-A fortune telling area. You can use the plasma ball, fortune telling set, fortune cookie cart, etc.
-A face painting area. You can use painting set, nail art set.
-A spooky area (like a spooky ride forest ,etc). Carnivals always have a haunted area.
For villagers: Pietro works great, Muffy, marcel as a mime. Margie, Merengue, Elvis, etc.
Anyways, that’s an idea.
Good luck! Don’t get discouraged!