There is an other scene I can think of that wasn't mentioned. I think it's right after Celes is kidnapped by Setzer and you are trying to convince him to help the cause. If Edgar/Sabin is in your party on of them will give Celes the double headed coin (priority goes to Edgar). If they are both omitted from the party, if I remember correctly, Celes will just pull the coin from her pocket and thank Edgar in her head before scamming Setzer.