Sinspawn Ammes is like 2 PC HP, so no way that Peppita, Meru and Kick come anyways close (In fact, that doesn't even get off half of it's HP). Meru really is so non-helpful with physicals. I don't think BoF 1 physicals miss, so average accuracy for Gobi.
Granted, things are looking a lot better on the third fight regardless, I think. There still a danger though (which I'll match out later) of Joker getting Lucia and then Augus opting to kill Songstress before Matador Song goes off (Even better, he'll kill Songstress in one hit with Joker in play, and then use the second hit to charge up). Note that Meru has to defend...or else he will use that extra attack to kill her instead of buffing up (although if she used the spell this turn, he may not care)
So playing with numbers, I first realize on mults listed, Peppita is about 10% above average on mults (Maybe a little worse. Adray and Sophia are stuck with Firebolt, but...I was just playing yesterday and Adray joined with better spells. Let's say that probably knocks her down to average, because Ice Needles is significantly beter). So she's about 60% to August
So: Monk (60)+Peppita(53)+Meru(55)+Lucia(Rages Monk)+Songstress charges futility->Joker MTs, bye Lucia; Augus kills Songstress, kills Meru
Monk (90)+Peppita (53)=3.1 (almost killing Augus, but still a little short)
Joker MTs (So Monk and Peppita have now taken 68% of average PC HP). Augus comes around and kills Peppita for sure.
Under this scenario, seems like they come close. They really want to get Augus out in two rounds. This could potentially be worse...if any damage sticks on that second fight. It's just worth noting because I think Lucia can use that Aromatherapy like 7 times. I do not know how many times she'll need to use it in the first match. But Meru coming into the third fight haven taken any hit=Joker's move KOs. I say this because I'm expecting Lucia's Aromatherapy to be pretty bad, and then it's getting halved. Either Songstress is using Silence, or a bunch of enemies are getting easy shots (which...maybe it would be better to let Sinspawn Ammes get multiple demis and shut off everyone else but EG minus some luck stuff. I...don't know). Of course, the half turn charge time on Matador's Song would probably mean that most of those physical fighters are going to get in a shot anyways, so Silence is probably best. I'm assuming Garland is 20% damage, Gobi is like 25%. Igglanova (assuming you let him attack round 1) is 15% and Evil Gaia will be opting for 12% Magic (that's a little AoE I think with Howl. Just to note that it probably gets two). So yikes...even letting the non Iggy people get a turn equals approximately 75% PC HP damage that one round. After the first Demi, Lucia is definitely basically going down. So yeah, both the 1st and 3rd fights have nasty aspects. If Songstress uses Matador, they will rush and kill her before it goes off. And while Lucia does have the awesome non-CT resetting revival...there is still going to be that time gap where that CT fits in (Not to mention that since Lucia is reviving at 1 HP, Evil Gaia will always be able to just kill Songstress the next turn).
If Matador was instant, would be enough for a pass I think, but that 0.5 CT makes a lot of things outspeed here. Kind of babble at this point, but yeah, it's does good when we are looking at some damage is sticking on that first fight.