Okay...total shot in the dark:
The "Worlds" will be supersized lands made up of multiple smaller lands and minilands. This has been my running assumption ever since the "Only 4 Lands" thing popped up.
1. Super Nintendo World
-The Mushroom Kingdom
-Donkey Kong Country
-Pokemon Safari Zone
-Expansion Plot
2. Wizarding World of JK Rowling
-Fantastic Beasts New York
-Fantastic Beasts Paris
3. World of DreamWorks
-Far, Far Away
-Island of Berk
-Trolls World Tour
-Expansion Plot
4. Holiday World
-Halloween (Uni Classic Monsters)
-Christmas (Rankin&Bass, Grinch)
In my head, the Main St/Hub is a mixture of all the worlds, almost like the intersection of a bunch of different Universes.