Her fruit won't work a against Zoro and he has a good enough Haki to not turn into stone by perfume.
I really think Zoro can take her on high diff because swords also give some advance Haki users some trouble.
Like Luffy with Hody and doflamingo with law.
The beam won't work, but the kicks will. It has never been stated that good enough Haki will prevent Hancock's perfume from turning you into stone. Even it it was, you don't know that Zoro has good enough Haki for it; the only Haki he's shown was cutting Monet's cheek.
That's actually not true btw. Here's what Luffy said about being pierced by Hody's sharp attack:
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which indicates that Haki isn't inherently weak against swords or anything, Luffy's Haki just isn't good enough for piercing attacks as of yet. Not only that, but Hody hit Luffy with a piercing attack, not a slashing attack, so it's not comparable to swordplay.
Doflamingo's strings has been shown to be as effective as any sword in the series so far, and Law's Koka stood up against it, which further proves that swords aren't an advantage against Haki users, it just depends on the strength of the swordsman and the strength of the Haki-user in question, and nothing suggests Zoro's is weaker than Hancock's or vice verse.
We really should avoid match-ups like this where we've barely seen the full extent of abilities that will definitely be brought up.