The story, which appears to also feature at least two members of the Legion of Super-Heroes as well as Robin, will be directed by Green Lantern: The Animated Series's Giancarlo Volpe. It's from Volpe that World's Finest Online got the only real details on the film yet available.
The all-ages movie will have a 52-minute run time, according to Volpe. WFO noted, that the film "features design work by Lynell Forestall (DC Nation), and includes the traditional Justice League line-up along with a few new additions, including Robin and Karate Kid. The voice cast for JLA Adventures: Trapped In Time includes Grey DeLisle, Dante Basco, Jack DeSena, Diedrich Bader, and Jason Spisak, with the movie’s score provided by Frederik Wiedmann (Green Lantern: The Animated Series)."
By traditional, of course, he means Superman, Batman, Wonder Woman and The Flash. Whether Cyborg is a member of the League here or an envoy from the Teen Titans along with Robin is hard to say. There's a conspicuous absence of Green Lantern, given the people involved behind the scenes on this video, but hardcore DC fans will probably be too happy seeing Karate Kid and Dawnstar interacting with the JLA to really notice.
There's also the "JLA" branding, which is an interesting choice since that's not how the comics have been branded since about 2005. Could that be a new kids' label for Target's Justice League stuff? Could be a good use of the trademark.