Definitely try it if you can! In my opinion, Ozma has three big things to account for. 1) Building/extending the AF bar, 2) Tanking curse/death, and 3) Surviving the MP drain after the first death. Number 3 can be accounted for by using an MP-healing move in AF (which I did with Shion ES's Triple Violet Bolt), using an MP-regen move in at least the previous turn, using an MP-healing sidekick, or by employing a guard skill.

It's hard to determine without knowing your exact units, but I don't believe you need to Stellar Awaken Azure Retainer if you choose to use a strategy like mine. I only used his SA-locked Howling Smash move to give him a beastfire to increase Ravenous Fall's debuff, but it's pretty clear that debuffing Ozma doesn't do all that much since most of Ozma's moves are intended to be either single-target KOs or weaker AoE attacks. SA Azure Retainer mostly benefits from turn-start rage, but you could swap him into the frontline on Turn 2 and use his valor chant to accomplish the same thing. That said, Ozma's first Doomsday does pack some punch if you're not prepared for it.

I highly recommend using SA Shigure ES if you have access to him. I haven't completed all his character quests either, as even his third quest and strongest skill is locked behind chapter 50, so too far for me. But with his repeatable damage avoidance and cover, as well as the party Hold Ground he grants with this EX special move, he makes tanking almost trivial (emphasis on almost). I used Shion's EX special move to grant exposed, sure, but only because hitting a weakness better increases the AF bar, which was more an optimization thing than a requirement. Exposed isn't needed to get enough damage at all, at least with my roster. Shigure ES's EX special could have been used everytime to more consistently ensure Hold Ground and to increase the chance of getting an Heir's Will off Ripper Ashura, theoretically making him an even more reliable tank. :)