I found a way to select added nondlc wrestlers. If you change AJ Lee's gender to male in X-Packer and then select Divas in game, AJ still gets autoselected. But since she is now male, we get a little selection menu too .
In this menu every male wrestler is listed. We can select our added wrestlers super easy with this. That means we don't need the catalog.dlc file anymore
This works on 2K14 and 2K15.