Square Enix have confirmed that Kingdom Hearts HD 2.5 ReMIX will be featured at Jump Festa 2014, via their official website for the event. The game will appear with a trailer and a playable demo at Jump Festa 2014, which runs from December 21-22, 2013.
The playable demo will consist of the following scenarios:
Kingdom Hearts II Final Mix
- "Halloween Town"
- "Beast's Castle"
Kingdom Hearts Birth by Sleep Final Mix
- Ventus in "Castle of Dreams"
- Aqua in "Radiant Garden"
- Terra in "Enchanted Dominion"
The following (small) screenshots for the game were shown on Square Enix's event website:
Unfortunately, Kingdom Hearts III is not listed on Square Enix's Jump Festa 2014 website.
Thanks go to @aibo_ac7 for the find.