So does Sackboy and Big Daddy. I already had the idea of 'Since Kat can fly and she already does a lot of menial job work, the King would ask her to roll up Heksville and she'd be like "NAW MAN THAT AIN'T COOL" and then they'd fight.
Ok, since the DLC will be in 2s and will be rivals, I'd say get the characters people really wanted. Tell me what you think:
Kat and Cloud would be rivals and there should be a Gravity Rush x FF stage. Crash and Spyro would be rivals and there would be a Wumpa Island x Spyro Realms.