When I did it I actually went and killed TFP first as he annoyed hell out of me.
I kept GAT, EP and DV as stunned as possible and if one got out of it used TM reduction by HS on it while new stun become available.
Both OB and CLS have basic attacks that can help control tanks on second application and make sure that those two tanks never get taunt off.
As I already said I killed TFP first followed by GAT, EP, DV and then two tanks but as long as you keep them stunned and TM controlled you can kill in order you prefer. In my case it was hard for me to see Thrawns debuffs due to all the other debuffs that tanks and EP had so I killed him first just to make sure he does not get out stunlock unnoticed and go wild
.BTW I did not use smokescreen at all with R2D2 but rather his basic attack for stun.