The problem I'd have with trying to use Wait Reaction to start a chain for Lucian is that Shiho can't just do it at will, a round has to pass after she's cast a spell and Lucian hasn't attacked. So even assuming Wait Reaction as unevadable (which I don't think it is, but it's more accurate than Lucian, I'd say), it's still a once every two turns thing. I distinctly remember that Wait Reaction -can- miss, especially if the target is too short or was knocked into the air.
Shiho turns off Yojimbo's evade, and an Oomphed Lucian does his work. Again. (With spell support from Rosa / Jessica if you respect Yojimbo's HP greatly, he's not dodging spells.)
Also... if Jessica is casting Oomph, she's not going to be able to add spell support. Additionally, if she's doing all the buffing and support, she's not going to be able to put a decent dent in the Magus Sisters with Magic Burst.
I'm -really- iffy about Monkey's chances on this last match (which I feel might be a bit too much, maybe if Anima wasn't around, it'd be more doable).
Quick rundown of potential sticking points:
Valefor: None, really. Not durable enough to survive a full-team onslaught, and not strong enough to scare Mew. Does drain a bit of Rosa's and Jessica's MP reserves.
Ifrit: Durable enough to at least get a second turn in. Mostly just a resource drain on Jess (buffing or whatever her non-fire spell damage was) and Rosa (probably just piling on damage with Holy).
Ixion: Durable enough to get a second turn. He might be potentially scary as he can heal away the damage from one round of full offense. If he does this long enough, he'll get an Overdrive and take out Mew (and probably Shiho) really early. But let's assume that stacking Might Reinforce, Oomph, and whatever Rosa's got on Lucian, and then spending the next turn with everyone attacking with their best (non-Magic Burst) stuff will take him out. This just drains Jess and Rosa's resources more.
Shiva: Dodgy whore means that Shiho has to cast something -after- Lucian's taken his turn so that she can get access to Wait Reaction on the next turn. Jess casts Oomph, and Lucian can finally do his thing on turn 2 if Wait Reaction connects. If WR misses thanks to Shiva's crazy evade, then she gets another crack at the team, which now starts draining Rosa's or Jess's reserves since Shiho needs to still have CT left to use WR.
Bahamut: Another durable sucker. Plus he can break damage limit with his Overdrive. I doubt he'll get a chance to do that, luckily. Hopefully Lucian still has some lingering buffs, and the team can put a significant dent in him on the first round. If he's not already buffed, then this is three more turns of Bahamut damage and Mew's running out of resources (or possibly dead, and thanks to Firefly, unable to be revived). 3 more rounds of Rosa wasting MP on Holy or Healing, and Jessica needs to be contributing at least Oomph to the damage pool.
Yojimbo: Another evasion whore. He'll live to see turn 2 at least, and that means Zanmato is possible. If Monkey really plans for this during Bahamut, he might be able to come into this buffed and have Wait Reaction ready. In that case, Mew probably took too much damage and died already, but the team will be able to take out Yojimbo in one turn thanks to the accuracy boost from WR.
Anima: If Mew wasn't dead yet, he's dead now. Anima's damage is ridiculous and he's able to one-shot nearly any member of this team. Assuming Jessica handles buffing Lucian and Rosa continues to spend MP to keep reviving a one-shotted Shiho (since that's who Anima would need to take out first after Mew to have any hope of winning this), then they should be able to pile on enough damage by turn 3 or 4 to take out Lucian. But at this point, Mew is dead, Shiho -might- be dead, Rosa is low-MP, and Jess isn't at full MP.
Magus Sisters: Jessica has to use Magic Burst here for the team to have a chance. Lucian's damage isn't MT and trying to pick them off one at a time with only him is suicide without Mew to soak up damage anymore. One of them might fall to Magic Burst, so let's be generous and say that happens, then Lucian and Rosa go all out try to take out another. Assuming they manage to stop the Sisters from getting any healing in, then the team manages to not waste too many resources here. Rosa has to choose between saving the last of her MP for the next battle or reviving Shiho, though.
Yuna: If Rosa holds onto her MP for this fight, then she has a few castings of Hold to scare Yuna with. Yuna uses Reflect, and Rosa uses Dispel. Lucian and Jess can try physical attacks, but Yuna evade means that it's very difficult to land a hit. Once Rosa runs out of MP (shouldn't be more than 3 turns), Yuna uses Protect and goes on the offensive. With no healers left, she takes out Lucian and it's game.
If Shiho is revived, then Rosa is out of MP. Yuna sets up Protect, and proceeds to put as much hurt on Shiho as possible. Assuming Shiho survives, and that Wait Reaction is accurate enough to get around Yuna's evade, then a Might Reinforced Lucian takes out Yuna.
Hey cool, I went into that thinking that I was voting against Monkey, but I think I just convinced myself that he more than likely wins. There are a few calls that have to be made in his favor (against Yojimbo and Anima mostly), but I think I'm voting
-pass-.