They arent so much extra scenes as different scenes. With only the three of them escaping Kefka's tower, a lot of the little ending scene puzzles are solved by only them. Like Setzer and Edgar pulling together to move a large peice of fallen metal (beat it with Sabin, and he catches it before it hits) and Edgar saying a few words about his brother.

The only scene that's completly original would be Terra in Mobliz, realizing her friends needed her and flying to them, then guiding them out normally. But that'll happen whenever Terra isnt in your party at the end.