I was just wondering if I was the only one around who's tried this. I had Celes, Sabin, Edgar, and Setzer (the least amount of characters when you get the airship). Celes lv. 91, Sabin lv. 76, Edgar lv. 77, and Setzer lv. 52 (He always seemed to die). I tried fighting Kefka 5 or 6 times before I succeeded.