Well instead of making MHera, I decided to go for Yomi Dragon instead on both of my accounts.
My first dungeon after that was to finally try MZeus and on my first try I cleared it (no continues), Yay!
I only made 7 combos, but I put
Akuma Shogun's skill (fire, wood, jammer, poison to dark and plus 1 to combo count for 1 turn) on Sephiroth, which gave me 8 combos total.
My teams were main: YD/Sephiroth/Hades/Eschamali/
Barbara
Sub: YD/DMeta/A.Ookuni/D.Kanna/Noctis
I used Hades' 25% gravity plus 5 second orb movement time, then Barbara's all board fire/dark plus 2.5x ATK for Dragon/Machine types. Took out MZeus in one shot.
I had Akuma Shogun's skill for an extra combo on my main side and Noctis' skill for an extra combo on my sub's side.
Now I can get to making RaDra on my main account as I picked up Zeus Dragon awhile back (had to use stones for it...) I'm thinking about using the extra MP I have on my sub to pick up RaDra for it too. (although I'd need to clear Zeus Dragon for it, too)
I also rolled once more on my main and picked up another Kenshiro. Why don't I get any FotN gold eggs on my sub...
Anyway, very happy to have MZeus cleared.