I hate Ozma. He's the only enemy in the game that can actually interrupt the ATB system and take a turn whenever he wants.

He also has 65535 HP, which is the max possible in the game. If he starts off with Curse or Meteor, then you're already in trouble. I recommend taking both Quina and Freya into the fight because both can do 9999 damage every single time with Frog Drop and that Dragon move. Some people will recommend you use Thievery on him to do 9999 damage, but to be honest I think you're better off having Zidane heal and revive. I stole for the entire game and at the end of it all my thievery was only doing 3000 damage. But hey, if you can get thievery to do 9999 more power to you.

You do not need to find all the friendly enemies to beat him. I beat him without finding the 9 or 10 friendlies. You won't be physically attacking him anyways, so it's rather useless to find them.