I finish GW every single time. I basically use only Lumi. You don't need a lot of healers.
I don't remember the last time I put in my 4 star Talia or my 5 star JC on anything other than a suicde squad. And I don't have a Barisse or Daka. Just Lumi. It must have been around level 70 or so last time I used either in GW (I'm 74, now).
I usually finish with one combination of my Arena team, just to piss someone else off. I sometimes use one suicide squad, sometimes none. I usually lose one of my tanks.
Also, in the first 3 or so nodes, obviously don't put in your weak sauce healers like Barisse or JC or Talia. Go all out offense until your protection runs down. Then I throw in Lumi lead for the passive heal for a few nodes, when it matters. Then when the punches are no longer pulled, I go with Arena type teams/leaders. Whenever there are two softies to end on, one Lumi heal is all it takes. Suicide squad or B squad potentially necessary against a node loaded with heal immunities and Savage and 555's.
Dooku L can help you get past tough nodes, even with low stars. When you can retreat and replay, the RNG Lord can get you by. But try to save him for when you need him until you get his stars up. AI doesn't save Dooku for last. Dooku L (and Dooku, himself) can change the battle at any time, so he's kinda like a wild card up your sleeve. And he will help you demolish jedi teams.
I can't see your squad in your link for some reason. But personally, I think having 2 or 3 tanks is more important than having multiple healers. Your tanks don't have to be high level. They can die and still serve their purpose. Anyhow, you will need a coupel of good tanks for Arena, eventually. RG and ST Han are both going to be necessary for a lot of squads. So I'd personally concentrate on tanks and/or Daka before investing too heavily in Barisse/JC/Talia for GW.
Barisse is overhyped for GW. I think it's because she is so limited in Arena, people who have her need to need her. She IS super useful in LS missions, though.