lefthandblack
Arcane
You are playing on hard, I take it? I was around level 85 in the final dungeon.
While the battle starts with a cheesy surprise attack, you can always intercept their turns with an S-craft. Kloe can heal your party that way if you are going to die before getting a chance to get a real turn. Also, a convenient way to get rid of bosses' minions quickly is to spam Joshua's Black Fang or Phantom Raid. You can just have other characters feed him Zeram Powder to keep his CP up and when all the annoying minions are dead, you can start fighting "normally". Zeram Powder is somewhat rare, of course, but it can be used on those few tricky fights.
Ahh, I did not realize that you could use S-crafts in that way. That is something to try. As far as consumables go, I have whatever I've managed to pick up through the game. I think I have some of that zeram stuff, so I can work that into another attempt somehow. I'm generally tl:dr when it comes to consumables aside from healing/magic. Thanks for the tips.