I've been thinking about using this Cherche, but i'm not sure the hp bane would benefit her panic ploy weapon refine. Should i just keep pulling until i get a speed or resistance bane?
Well, the atk+ is way more important.
You can always just build her without the refine, she doesn't fully need it like some others. And when you draw a +atk, -spd/res you can merge this one into her and refine her weapon then.
I have a cherche with the same ivs, though I don’t really think that her refine is that good. Regardless of her ivs I feel that a att or def refine suits her better than panic ploy