We’ve seen Lightning and Kain in their usual outfits. How do their second "another" costumes look? Like this.
Dragon scale armor is a nice touch for Kain. I wonder what Square Enix will make for his third outfit. Everyone in Dissidia 012[duodecim]: Final Fantasy has three costumes, not including downloadable costumes such as Lightning’s Aya outfit.
The official Dissidia 012[duodecim] site has a tab for DLC. It only has crossover costumes from The 3rd Birthday and Kingdom Hearts: Birth by Sleep Final Mix now, but since there is a tab Square Enix probably has plans for other downloadable content.