She's facing off against the Others, but hasn't actually fought one on one with Aquaman. Cheshire did battle The Red Hood and the Outlaws solo. She has tech that allows her to teleport and turn intangible, IIRC. So, LB is going to definitely need those powers.
Does Cheshire still have that poison? I recall Pre 52 it was enough to bring Slade to his knees, but then again it was written by Eric Wallace so I don't know if I'd put too much stock into it.