Today's patch to GW has greatly increased the difficulty. I was able to clear it with the same team and guidance except my poor 4* Dooku failed on me about 10 fights in and I had to sub in Phasma (my only other 7*) to finish.
The only words of wisdom I have currently is retreat a lot and try different combinations, because if you cant end the fight with everyone at 50% hp or more they probably wont live long enough to get healed.
Also healing immunity characters go from being removed early because they were annoying to a must kill ASAP.
@Tony167 I would need to see who you have, someone like Luke could replace Dooku, they are both pretty fast and can stun. Luke doesnt have as much Jedi tech or as fast though. As long as you have Sidious or Kylo you could probably do without the other. Barriss can work in place of luminara but really you need one or the other.
@Ivadek You have to still try, who have you been farming in Cantina? Geo Solider is pretty good but 1* won't get you that far. I had started an alt account I cleared it with yesterday (first day I was level 40) with Dooku (my only bronze pack character pull oddly enough), JC, Talia, Luke and Jawa all 3* with pretty high gear for level 40.