If Destiny Islands didn't fall to the heartless in KH1, what would have happened to Sora, Riku, and Kairi on the raft? Where would they go? How long would they be gone? Were they really going to eat those raw fish and a raw seagull egg (presumably fertilized and carrying a seagull fetus)?
Where do the waterfalls on the play island of Destiny Islands get their water? Do they have a giant leaky vat holding rainwater up there? Is it a freshwater swimming pool? Or did they just have a rain, and rain is draining off?
What is outside the gates to Traverse Town? Is there anything outside the city? Where do they grow their food? Where do they generate their electricity? Where do they get the supplies to sell in their stores? Why are there no bathrooms anywhere? Why do the triplet ducks sell shields and magic staves? Do they have many clients looking for these items? How do they make potions and ethers? Are potions and ethers canon?
Why is there a universal currency? Did all worlds just continue using Munny forever after the Keyblade Wars?
These are things I have to know.