User blog comment:Rassilon of Old/Silhouetted characters on the Young Justice: Invasion poster revealed!/@comment-68.90.123.49-20120502220514

So Robin, Blue Beetle and Wondergirl. I'm thinking the other three are Speedy, Static (Can't be Mal because hes muscular and the guy in the poster looks a bit scrawny) and Impulse (the hairstyle is a bit to different than KF's)