Ehhhhh this is kind of what I was afraid of; I've got decent 13 synergy (Lightning's Peacemaker, Hope's SSB and Fang's Partisan) but no Medica, but an all 13 group also means no wall and you can only RW one or the other. I'll give it a go later but not expecting great things.
Not at all and my 13 synergy is worse then yours (sazh deneb duelers, vanille's deprotectega, hope's original boomerang, fang's pulsar)
Give it a try! I managed to Master the CM+ for this event with even weaker synergy than both of you (even if it got real hairy towards the end).
The only characters that had meaningful weapon synergy was Lightning with Peacemaker (that I thankfully managed to grab in the Celerity banner, thank you RNGesus) and the NY Gun which got slapped on Sazh. No Medicas either.