I had these thoughts in the Headcanon thread, but they don't really fit there. I'm not sure if they fit perfectly well here either, it's just the best thread there was:
I was just thinking how it's a shame we've never got at least moments in an ending scene or even in the End Credits of Sora showing Kairi flying in Neverland and taking Riku to meet Santa Clause in Christmas Town. It would've been perfect with KH2's ending, especially since they did callback to the cave drawing Sora made in the Secret Place, too. It could even have just been a still shot of Kairi and Sora flying in front of the clocktower with pixie dust around them and a side view of Riku shaking hands with Santa while Sora grins in the snow area in front of his workshop. I like to think those things have happened at some point between 2 and 3D, only off-screen.
Another thought came to mind jumping off of that one of how interesting it would be if the circle of trees that connect Halloween Town, Christmas Town, and the other holidays also connect those worlds to Quadratum. If Quadratum turns out to be reality and the KH universe the un-reality... Well, I know I've had this idea before that maybe Enchanted's animated world, Andalasia (?), could be connected to Quadratum through the well Giselle gets pushed into and you end up meeting real world Giselle in Quadratum (which isn't very different from NY with all the skyscrapers). The same could be the case for Halloween and Christmas Town. The world inhabitants there are always preparing holidays for the real world. Perhaps there could be a door among the tree circle that leads to the real world. And Santa's sleigh can also travel to Quadratum perhaps? The same way Hook's ship and Monstro can fly through KH-verse, except Claus has magic that's special and could travel to a place like Quadratum. It would make sense since the Fairy Godmother uses Nameless Star's connection to someone from that world as a way to travel there--Santa has an emotional connection to all children there. Maybe even the same way as Fairy Godmother, through the dreams that children have of the things they want? I might be wrong though, I'm trying to remember what the Nameless Star's purpose is in getting Riku to Quadratum? Is it her body that's still there even though her heart's in the Final World or is her memories or connection to someone there?
Anyway, I know many have pointed out how Quadratum means Square. If Cloud and Sephiroth (as well as the TWEWY characters) actually were there because that's their world (the real world), it would be interesting if that world is sort of the reverse of the KH-verse we've seen so far where Disney characters are the minority while the FF ones were the majority. Something like Giselle being lost in their world would be almost a reverse situation to the FF characters being lost amidst Disney characters in Traverse Town in KH1. I know it's likely not going to perfectly turn like this, but it's interesting to think of ideas like this for the story.