I finally managed to clear t4 with them at 5* R2. I believe Speed and Health sets on Luke, Offense and Crit Chance on Choda (CD triangle), and I think either Speed or Offense and then Defense on Barriss. Of course as much speed as I could get on all.
Restart if one has too little health by the end of p1. P2 focus on DDK (use specials to clear damage immunity), pass turn to Choda if you can. Self heal on Barriss or Choda if they get low or you think DDK is about to unload. B2 next.
P4 I took out Savage first...tried to make use of Luke's buff disruption for that...don't know how much it helped. Mainly try to knock him down with Choda. Maul didn't seem awful after that.
Fairly RNG-dependent.