Heya, I created an account just to say this here. I hope you enjoy it.
I noticed an odd disparity in the trailer. Here it clearly states that the game's audio and text will be in English in the final product.
But, the opening cinematic has two characters conversing in English. A close up of the mouth shows that the lips move according to the text. (I'm not sure if localization of cutscenes requires a lip sync.)
During gameplay you can clearly hear Goofy say Come on! and Sora say There!, Take this!, Let's go! and another Come on!. This could very well be audio from older games. But why go the extra mile for that when they could've muted it like other trailers?
So this leads me to believe audio localization is at least partly done.
This would be in line with their previous release of KHII where they announced way too early and around half a year after their first real full fledged trailer, KHII was released.
Last note! In the trailer we can see a calendar that, if you assume is in American format with the Sundays on the left, coincides with October this year or December 2016. Might be a very lucky coincidence, but who knows?
Thanks for reading my tinfoil theory and I hope you enjoyed it!