DFFOO [JP] Minwu just works: Off-turn play with Vivi FR
31Minwu just works with some many things, even if he heals and Vivi's FR has a 20% just for not being at max HP. Even without the stage HP poison, it would still be a 800%+ play with around 4T left. He is one of the long standing MVPs in a team.
I actually did this with the typical Ultimecia time warping stage in Ch9 pt 1, but she just dies too easily before the good bits happen. Sad that the barrage of 3 target fights was temporary and now they are gone, so I can't really do it in a meaningful 3 target setting (not going through CoD again lol).
Lulu LDCA
Lulu's LD stock value has been rising lately. Ofc you can also use Neon BT, but in case you want someone else in the party or you don't have her BT (like yours truly here), it is a very convenient way to bypass the inherit elemental attacks for any fire FR.
Minwu
Minwu's trap healing can make you potentially miss out on the 20% FR condition. One way to get him to work is to let mild boss dmg go through or have the HP poison take away a chunk of your HP. Here I let go of WoL's ribbon buff so he can also get poisoned (though he got it late, so he doesn't immediately get to V stacks).
Another way to get this to work is to use turn manipulation. If you can get Vivi (or have Cecil BT in general) go before the party, particularly in front of Minwu with no boss turns in between, Minwu's HP will be drained before his turn. Therefore the 3rd party member and Minwu can both enjoy those bonuses. Vivi may potentially lose the 20% himself, but it is better 1 than 2 people running into that situation.
In any case, Minwu has so many trap triggers that the 20% loss is quickly covered by the myriad of procs. Coincidentally his HP+ also triggers every trap in the field, so that satisfies the bulk of the bonus requirement of Vivi FR. Minwu does have a slight problem of buff/debuff falling off so look out for that. Usually by the time his buff runs dry, the FT should be over.
One drawback of using Minwu and Vivi together is they are both staff users. So in this case Minwu's dmg is somewhat limited by mBRV and overflow. He also does not provide HP dmg cap up on his BT.
3rd party member
WoL is mainly here for the shield. Other characters with more off-turn dmg also work well. The only problem to be solved is to ensure your entire team is well protected.
For example:
Gladio:
Good party support and just an impenetrable wall that happens to not get debuffed ... and he happens to counter things.
Kain:
Good carrier of Lulu LDCA. Jumping in Vivi FR also gives full bonus because it is a BRV attack. 30% cap increase and giving more turns for Vivi and Minwu to work. Alternatively a lock call can draw fire where no ST attack can hit him or just reduce AOE dmg overall.
Yang:
Like Machina and Minwu, multiple counter procs. Very good for off-turn dmg. Though you may need some mBRV/ATK CAs.
Machina:
Disgusting HP+ (burst) to go with Vivi FR, multiple counter procs, 30%HP dmg cap up and has innate dmg reduction. He is a good WoL LDCA carrier since his EX counter needs him to actually get hit. Like Yang though you would need some support CAs.
Some on turn choices:
Sherlotta/Aerith (Y'shtola/Yuna as honourable mention):
Huge dmg HP+, force chargers and support. Though having them would mean the inclusion of HP regen. That may be a factor for consideration for Vivi FR condition 2.
Special mention:
Yuri:
This is a surprising one. Special thanks to viewer Astral_Ragtime's intriguing inquiry about Yuri's interaction with Vivi's life drain.
To reiterate, Yuri's Chelinka buff prevents him from getting HP drained by Vivi. So in that regard he is in conflict with the second condition. In this particular fight, the HP poison debuff is so strong that his regen would not be remotely enough to cover the HP loss.
The good thing with Yuri is his BT has a blind aura. So for bosses that you can dodge, you can get drained all the way to 1 HP without any worries.
Another thing is once setup, his BRV+ is one of the hardest hitting AOE BRV/HP attack to this day (think Rinoa's Ultima but with conditions). It is also instant turn rate that consumes individual stacks, so on 3 bosses you can use it 3 times in a row.
Vivi:
Overall Vivi is dishing out BIG dmg rn. I didn't have any problem with his longevity before even in the Shinryu era, and now it is certainly not a problem with effectively 40 turns (8 at QS + 4 LD) of embers of darkness.
The Double Fire+ spam during BT may seem braindead, but it actually requires some intricate setups. Reason being his LD stacks still decreases and it has the same duration as his BT. To let all of his LD/BT cover all of his BT phase, you would need to refresh his LD stacks first after FR/BT. This would also require you to have used EX and FR once prior, should you choose to use his FR echo after BT. For now I do it like this:
EX - FR - BT - LD - FR(e) - BT phase with DblFire+
If you don't plan on using the FR(e) again then there is a bit more freedom.