Oh it was taking too long to get replies so I just went ahead and fought with the set up I had. I died tree times, but ultimately won once I got to Sephiroth. The part I kept dying from was from the rainbow Bahamut's Mega Flare. I had to make sure everyone had Shell on at all times to make sure I could survive it.

@Mercen-X I didn't know Bahamut was in this game. All I had were Ifrit, Shiva, and Fat Chocobo and I thought that's all you get.