Naw who they should team up with is Krystal*Light, it will be combined and would say Final*Krystal. There would be 30 characters to choose from, you select your two parties of 8 to save the universe from destruction.
My personal party would be: Tidus, Andrew, Malaya, Squall, Nick, Vivi, Zaden, and Lyde Lyde from Krystal*Light 7