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.