If you main Bayman a tank roll will crush highs and some mids. Not to mention it has sidestep properties. If they're doing pokes that may be your best bet. Of course, some mids can knock you out of it but you're going to have to use your best judgment.
As for lows...well...good luck with those online. lol. A sidestep works against some lows. You could also. wait until they throw something out that's unsafe then punish.
Bayman's rolls destroys most of Kasumi's stuff. then when she starts doing her obvious lows to stop the rolls, break her legs with an oh so satisfying advanced hold.