+atk -HP (boo superbane but I don't want to give up her spd because now even Lilina might double)
Wrathful absorb+
Martyr+
Miracle
Brazen atk/def (or atk/def bond or close counter)
Bowbreaker or guard or dazzling staff
Atk ploy
Spd ploy or close def
Could potentially get her defense into the 30s if you count the ploy, and she heals when she gets hit. Seems decent to me. Lissa can't do this better than her because Lissa doesn't ploy as well.
I really like the Close Counter/Close Def build on healers too, because they can self-sustain with absorb. This sounds like a really great Mist! The +Atk is definitely nice.
For her B slot, I would suggest running Guard, because Dazzling Staff is only useful when applying debuffs, special effects or Pain+ on player phase, really.
Pokemon GO
Fire Emblem Heroes
Fate Grand Order
Dragonball Legends
Dragalia Lost
IV Calc
Heroes