http://worldsfinestonline.tumblr.com/post/24203585455/images-from-young-justice-bloodlines-to-be
Totally Heatwave. And Gar looks ticked off at Impulse. Maybe Impulse said something bad?
http://www.youtube.com/watch?v=wg981zg-g-k
So, they're keeping Impulse's origin as a time traveler, so it seems!
UPDATE:
http://www.youtube.com/watch?v=R3FQWB2-rtU
This isn't Bart's first animated appearance!