W! Lissa

Heya dude, I'd say keep the +res one and sac the other one to whoever you'd like for Bold Fighter. With +res, she reaches a beefy 37 res, which lets her easily tank mages if you wanna run DC with that. You could also run a ploy, probably Def Ploy if you wanna do more dmg or Atk Ploy to increase her tankiness.

Sinw Lissa is a armored tank who'll be taking more then 1 or 2 hits I'd recommend + res because it will further increase her magical bulk. To patch up her def I'd go for the def refine bexause then she'll have a 36/36 defensive statline.