Sweet Tooth's aerial square -> down square -> down circle -> (walk forward) up circle -> jump side triangle doesn't work on Kat. The up circle will never connect. I thought maybe my timing was off so I tried it on Raiden and did it my first try. Maybe it has stricter timing, but I think it simply doesn't work on Kat.
Nariko's down circle, which stuns the enemy long enough to follow up with any attack and go into several AP bursting combos doesn't work on Kat because she collapses too fast. --- "The more you sweat in training, the less blood you lose in war."