Okay, after reading her powers I think that the only useful things are the Duplication and the Stat changes since:
- Zoro has no hax Rosalyn can null.
- Zoro has no magic nor any related energy to get nulled.
So this comes down to a regular fight. In AP they are roughly comparable but he probably holds a slight advantage. This is her scaling chain from what I got in her profile:
62 Kilotons = Evil Chairman << Stan = Rosalyn.
While Zoro's goes like this.
65 Kilotons = Casual Enel < Sanji << Semi-casual Enel < Zoro.
This is meaningless since she can buff herself and debuff him.
In the range department Zoro wins so they start at his range. He also holds the stamina and most probably the skill advantage. Dunno about experience, but they are around the same age. Zoro has been training since he was a child and has been defeating people likely stronger than him even in poor conditions (i.e. Hatchan) and with serious injuries.
Her duplication might be a problem, but Zoro can handle more than one enemy at the same time (Sham and Buchi) in a worst scenario when he wasn't as skilled as his Skypiea version.
On top of that, he'll be especially careful with the lightning attacks after facing Enel (this version of course) but with speed equal he will not have the same problems and Rosalyn can't turn intangible.
So yeah, after a long fight Zoro should win with his superior stamina and experience. If Rosalyn has good skill feats I might change my vote.