So i bought the Zack DOA5U COntent pack, which gives me his halloween costumes essentially. As there is not catalogue as its already built into the game, it should just unlock, but its still locked in the game
I had an issue like that I think for Ein, bought his 2014 Christmas DLC but when I went to the game, it wasn't there. It took me a year to realize to look up the costume in the actual psn store so I could unlock it since the costume was there but wasn't unlocked.
I'd say if the costume(s) is just there and locked, go to the psn store and look up the costumes manually and you should find them available to just download manually, that's the only way I could unlock Ein's costume since it wasn't in the in game accessible DLC store where all his content should be.
I bought Dizzy dlc for Guilty gear XRD, I closed the game and started it again, and still nothing, but I had to turn my console off and start it to make her appear, maybe that helps for you.