Well you don't really need Cerberus and you can refine some Holy Wars from the Gilgamesh card. If you don't have that and you haven't junctioned your characters properly than you're screwed. You need to at least take some GFs from Squall and give them and some powerful magic to Zell and Irvine to boost their stats. Proper junctioning is the key to beating this game.
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Poets have been mysteriously silent on the subject of cheese - C. K. Chesterton