When Kitty has Dudley's brain, she speaks with Dudley's voice. This is the same thing that they usually do on The Fairly Oddparents. This goes for Verminious Snaptrap as well.
R.I.T.A. makes a return. In the end Keswick says "this can go with my over failed experiments" and throws the brain switching gear in a locker. If you look carefully, you can see R.I.T.A. on the top shelf.