With regards to other Squenix games with DLC, check out the news this week that Theatrhythm: Final Fantasy now is confirmed to come to the West. That link discusses Europe specifically, but the release was also confirmed for North America on the Square Enix Facebook page.
Kingdom Hearts: Dream Drop Distance is coming out in Japan next Thursday, a release that has been anticipated since the Nintendo 3DS was announced. With the game all but out now, video from the Premiere Event to show the game and celebrate the tenth anniversary of the franchise showed up online. Additionally, an advertisement made from game footage and clips of the event has been on the air in Japan. andriasang has both on one convenient page for KH fans.
Finally, a new domain has been registered and a teaser video produced for a mystery new game, apparently to be released this Summer in Japan. Rumor has it that the game will be called Crystal Conquest, but no other details are available. Kotaku guesses that it will be a smartphone game, and that seems like a pretty reasonable guess.
Source: andriasang, Square Enix Members Europe, Kotaku