on this YJ tumblr http://youngjustice.tumblr.com/ it has some pictures of new characters.someone won a deck of YJ deck cards which had new characters.one of those characters was Zatanna,Zataras daughter. Also greg said that there was a reason that Zatara was a member of the JL and Zatanna wasnt.
http://s3.amazonaws.com/data.tumblr.com/tumblr_lovhmi9DvN1qgn0a6o1_1280.png?AWSAccessKeyId=AKIAJ6IHWSU3BX3X7X3Q&Expires=1311888171&Signature=OKnTH8sJwOoJgBAn7%2FsusknFrbs%3D <-to see image in full size
visit the YJ tumblr(link above)