I want to propose an idea… although we can place regular furniture outside in New Horizons, I feel like Pocket Camp also gave a tease as for what will be replacing Public Works Projects: Amenities. I could see Amenities being the new type of expensive item we build for our towns in this game. Maybe we can build amenities later on in the game when Isabelle arrives as our Mayor, or assistant (if we are still the Mayor).
Amenities are not as simple as they are in pocket camp though. For example, instead of the tree house amenity being an awesome tree house that is just for show (and for villagers to be seen sitting in), perhaps it could appear even larger on the outside;players can actually go inside and decorate their own tree house! This would make the amenities as seen in Pocket Camp have more of a use in New Horizons, and give players more areas to hang with friends. More amenities I could see become bigger and more useful is the Pool and Halfpipe! Imagine being able to go swimming in a massive swimming pool with friends, or skateboard on a half pipe and do tricks as other villagers and friends watch! I could totally see this happening, and it would make towns even more exciting.
It sounds like your island already develops over time so this seems like it could be a natural progression of that.
Personally I don't think I would want any of those though. With how small the island seems I wouldn't want to devote space to any of them. Of the amenities in Pocket Camp, a pool sounds the coolest but I think a pool on a small island would seem kind of silly.
Let's go Gophers! Ski-U-Mah!
Sorry, I don't accept random FCRs.