Here's some news. Appearently, Big Hero 6 was the last chosen world to be included in Kingdom Hearts 3.
Now before you panic, no, it's not the last world that's gonna be revealed, there is gonna be more. It was during development that Big Hero 6 was the last addition to Kingdom Hearts 3. They have already picked other Disney worlds first and Big Hero 6 was the last addition.
In other words, the latest disney movies that came out won't be included in the game, in other words, no Zootopia or Moana . But we can be happy knowing that Frozen and Wreck-it Ralph may be included.