This is all I did:

Tidus: Hastega and attack
Yuna: Auto-Life everyone and Holy (I didnt need to, but summon overdrive anima if your HP is low. Mine was at 9999.)
Lulu: Ultima
Auron: Attack (with celestial weapon to break damage limit)

It was over in 10 minutes. I thought Braska's Final Aeon was harder than Sin. Yu Yevon was incredibly easy, also.