If you have a savedata of "Street Fighter X Tekken" in your console, it will automatically unlocks five extra costumes for them. Beware! These costumes aren't the ones of the USFIV preorder, there are the ones from SFxTK. As Decapre isn't in the game, they give her the Cammy's one.
To enter these prize codes, simply access the Player Data screen from the main menu. At the bottom of the list of available options, "Prize Code" should be visible. Selecting this option will pop out a text entry field which should be filled with the following strings to unlock their respective titles.