FF6 gets events fairly frequently (just not MONTHLY the way FF7 does), so Mog probably gets his MC2 in the next one. My prediction is the next FF6 event will be some sort of Empire related event, releasing Kefka's MC2, re-releasing Terra's BSSB on the banner (Tidus and Cecil just had similar treatment), Celes gets an En-Ice Soul Break which is a running trend now, and Leo will be a new character because he's apparently in high enough demand and if they made Braska a character in a recent FF10 event...well, no, Braska is more important in FF10 than Leo in FF6 is, but Leo was actually playable!
Mog will probably be tossed on there because "Why not?" situation; he was put in with Locke/Shadow's event for an MC1 for similar filler purposes after all.
For simplicity, given my team, "Beatrix" refers to the PC, and "UBeatrix" refers to the boss.
That said, mastered Ultimate Beatrix. Planet Protector failed, I tried a Seiken Stock Break RW strategy for flexibility, then learned it has a LOWER RATE than Shadowsteel, then went back to Banishing Strike on Steiner, and Shadowsteel on Tyro. It was brought to my attention that Full Break + Steal Power/Power Breakdown wasn't really much better than one of those solo, so I decided to tweak things a bit and give Tyro Lifesiphon. I don't need Sentinel Grimoire until after Climhazzard to prepare for Stock Break and Holy, but being able to KNOW I'll have Sentinel Grimoire ready later in the fight at any given moment to pop when Tyro has a spare turn? Yeah, that made a meaningful difference since my best Mitigation was never down. His damage was superfluous as is, since with Hand of the Emperor + Armor Break, he was doing like 2400 with Lifesiphon, so whatever.
Used Hand of the Emperor as my RW because that worked on my victory run; it boosted Vaan's damage to near 10k per shot with Tempo Flurry after Steal Power, and had a similar effect on Zidane, gave me a slight defense push, and made Steiner's Armor Strikes hit really hard, so only Beatrix was really suffering on the damage end compared to Planet Protector (again, Tyro's damage sucked regardless.) The damage boost my Thief gets from HotE offset the damage loss from PP Beatrix.
My set up (not putting equipment; just know it's all 5* stuff with only synergy being Yuna using Garnet's Storm Staff and a few 4* FF9 Power Belts.)
Beatrix: Memento of Prayer, Armor Break, Freedom's Wish.
Mostly exists to be a semi-tanky character who can cast Memento of Prayer to offset Stock Break's Sap at will. Armor Break was R5, and it boosted Steiner and Zidane's damage slightly, so felt about as good as any; her damage did register unlike Tyro's, but it was also the least important part of the fight. Worth noting she also had Mystery Veil for Mystic Prayer, since it was an extra 750~ MT Healing to use after the 2nd Climhazzard, when the HP push could be necessary.
Zidane: Tempo Flurry, Steal Power, Katana Master (he was using Auron's Shimmering Blade).
On hindsight, he should have gotten Freedom's Wish since his damage was more important, but whatever, pretty straightforward what his role was. Steal Power -> Tempo Flurry x2. Steal Power's slight increased time over Power Breakdown, and Tempo Flurry's fast charge times, he could always act twice in between.
Tyro: Using a ranged weapon (Aevis Killer), Shadowsteel, Lifesiphon, Dr. Mog's Teachings
Exists for Sentinel Grimoire, inflicting Sap, and...that's about it.
Yuna: Protectga, Curaja, Mako's Might
Healer, who has HotF to counter Climhazzard.
Steiner: Armor Strike, Banish Strike, Dragoon's Determination
My 2nd highest damage dealer after Zidane, gets BOTH the medal conditions, and is a tank so adds that extra layer of reliability.
The big thing about this fight was getting Yuna enough turns to have Hymn for the 2nd Climhazzard. Getting her Sapped early screws me up here, so I Lifesiphon the first few turns since unlike Full Break, timing is pointless on that skill; +150 Soul Break is +150 Soul Break, so firing off a few shots early is better than later. Shadowsteel spam after first Climhazzard to get her sapped and that should be good for most of the fight, hopefully reapplying it on subsequent ones so it doesn't run out. If I get Sap too early, I'm hoping she hits Yuna a bunch to get her gauge high enough for HotF after the 2nd Climhazzard. If I inflict Sap AFTER the first Climhazzard? Yuna should get just enough turns, especially if UBeatrix hits her once or twice to get HotF ready. If Sap doesn't connect, I'm basically SoL since the DPS it adds is massive. Naturally on the winning run, Tyro gets Shadowsteel to hit on the 2nd attempt or so, which is adequate. After first Stock Break, Beatrix casts Memento of Prayer to insure I'm not sapped after the 2nd Climhazzard, otherwise spams Armor Break, while Steiner and Zidane just do their things. Yuna's turns are the real key one, since I need to make sure Protectga is always up, need to make sure I use Curaja fast, and make sure I keep looking at Beatrix's health such that Yuna can start charging HotF the instant Climhazzard gets used.
Worth noting that Steiner was the one to use the RW both times since his damage relies on it more anyway. Also because UBeatrix decided to murder Beatrix with Holy late in the fight anyway. Thanks to there being no special death condition, I went with it; Beatrix's damage as I said, while not pointless, wasn't integral. If Stenier or Zidane died, I'd be screwed thanks to lack of DPS. If Yuna died, I'd probably be screwed too since Curaja insures I can always survive Shock, and not having that is scary. If Tyro dies...meh, whatever, Sentinel Grimoire was already cast, so he was expendable too. Basically, Holy cna kill off one of Beatrix or Tyro late in the fight and I'd be fine; the other 3 not so much. So UBeatrix offing Beatrix wasn't a big deal.
So yeah, glad that's over with, let's actually finish the Elite part of the FF12 event now!