Any character you dont get, when theyre section comes up in the ending it just has a shot of a town or something related to them and it pans across with theyre menu portrait on the top left of the screen.

(SPOILER)Terra will fly to the tower after you beat kefka regardless of whether you got her or not so her ending is the same.

(SPOILER)There are minor changes in the endings for Celes and Edgar. When Celes falls Setzer catches her instead of locke and when the iron bar falls celes and setzer hold it up instead of sabin. The bit afterwards when theyre on the airship changes abit too as the other characters dont appear.