Oh god.. I almost cried seeing that thread title...

Celes is not optional. When you first get to South Figaro is when you meet shadow for the sake Shadow runs off alot, that's why you don't get him then. Plus Edgar's all "OMGHE'LLSLITHISMAMA'STHROATFORANICKLE" and they're all "OMG!!!" and so then you leave, go to Mt. Koltz, returners, Lete river, then the three Scenerios, There is -no- way to not get celes. The only way out of the big mansion you have to go to is through the basement because all the other exits are blocked by gaurds. Right before you walk infront of the first beam, it does one of those scenechanges on it's own and goes straight to Celes' thing. So no, Celes is not an optional character. =]