I ran CLS R2 Leia Thrawn or Chirrut and OB for a while. I didnt have his zeta at the time but I think zOB is better than GK because he solves fracture. RHan would be fine to replace one. Tip: Make your Leia slower than R2 and she can attack a turn early because she is already stealthed.
This was before Sion so you have to control him first or make your R2 slower. Nest is also an option to replace Leia or RHan. Daze makes team Palp cry. Also usually had Thrawn swapped TM with Old Ben so he can open with mind tricks bc if you can get mind trick off early it almost guarantees a win.