Turns out that I can beat Zeus Mercury consistently after all. I thought the first floor golem might be a deal breaker, but he gives enough time that I was more than able to burst him down with rows. Used a Metatron friend just in case the golem bound Valkyrie and to help me beat Hera-Is without using any skills. Hermes took forever because he used Hypnos Letter every third turn at least, but again I had Metatron, so I was fine. Zeus himself was not a problem even though I botched by combo on him and only got one row during my big burst, but if you hit him below half he gives you three turns to kill him before he does anything, so I was fine. Took quite a while, but not bad at all. I want to throw the Flampy into Misato like the others, but I guess I should save it for Awoken Horus or Awoken Kagutsuchi at this point.
Now the only thing left aside from the very early easy dungeons is Zhao Yun, who I'm actually much more scared of than I thought. I was thinking maybe I could grind him down with Gabriel after all, but I forgot that he has a maximum combo shield AND status immunity AND blue resistance. His combo shield is too big to plausibly kill him with rows, and it makes slowly grinding him down to kill range implausible. Might have to give Verdandi a try, she might be able to handle him.