Why do you want Crono though? Of all the characters you could take, you would take a goklone over a fire emblem character? What would his moveset even be?
A sword fighter with lightning magic? Sounds pretty unique to me.
Also, the whole "what would his moveset even be?" question gets real old and I'll give the same answer to it every time.
Look at some of the characters already in the roster that never actually fought in games. Captain Falcon, Game & Watch, Duck Hunt, Captain Olimar (while the pikmin did fight, you were just there to command, rather than fight), Wii Fit Trainer. I'm sure there's more.