I'm fine with Cathy, but Kamui is a pain to space against. You really have to be systematic in your approach or else she'll just swat you away. Be careful about 4GC Tenza, it will tag any of your limbs you have sticking out. When you show that you can deal with that, there is not much the Kamui can do to get away.
Run Tyr on Cathy, seriously.