When a fan asked about the fate of the Johnny DC line, Didio teased that a Young Justice comic would be on the way, along with the new TV series. He also said that "There are [kids] books in the works....they're really not cancelled. A bunch of stuff is coming your way."
As Kevin pointed out earlier this week, both Billy Batson and the Magic of Shazam and Batman: The Brave and the Bold's October issues are marked as the final issues of those titles. The final issue of their all-ages Super Friends title came out last week.
But it sounds like they're just being replaced with something different, which I'm sure we'll hear more about on Sunday at the "DC Kids: Aww Yeah!" panel.