I spotted something pretty interesting from an aerial video posted by Attractions Magazine on YouTube (it's from a drone so I'm not sure if it's allowed to be posted here). Super Nintendo World doesn't seem to have the slot machine mini-game from Universal Studios Japan. Instead, there's a new path extension with planters next to Peaches Castle. Are we getting an exclusive mini-game?
Edit: You can see it here. The area next to Peaches Castle with the construction stairs isn't open in Japan. I compared it on Google Maps.