I heard if you open the case when Zell and Rinoa are in your party and exactly 8 hours and 88 minutes on your game clock, you travel back in time to the very beginning of the Sorceress era. Zell then expresses his hunger for a certain processed meat in a bun, which confuses Rinoa and she uses her powers to turn the entire party into hotdogs. At which point the first sorceresses eat the hotdogs and that is how they absorb Rinoa's powers to create the sorceress line. Of course, it's game over at that point so you'll need to reload a previous save to continue.