I was just coming back here to elaborate more on Stitch when I saw this! Honestly, I had pretty much dismissed Lilo and Stitch. But thinking about it being set in space once again has made me change my tune. It would protect the plot of the original film and it would be totally different from what we have so far. Stitch as a true party member would be a lot of fun too. We also still don’t have a Disney world that seems to tie in to Terra and Aqua yet. Ven has Monster’s Inc to an extent through Vanitas, but a Stitch world could tie him in as well.
As for the likelihood, honestly, as fleshed out as the Gummi ship stuff is, it would almost be a shame if there is no world set in space.