That really is bad art. They can't have gone BACK - this is the same visit. They shouldn't be so excited if it's a return visit. But Superman being there is a continuity conflict - odd, since both books are by Bendis.

Clark only knowing Tim, Cassie and Naomi is not a continuity gaffe, however. They are the only ones he would know after New 52 - Superman Reborn established that while the New 52 Kon was gone, he didn't remember the original Conner, and the same thing can be presumed for Bart. Teen Lantern and Jinny Hex are new, and I think he genuinely hasn't ever interacted with Amethyst.