She punishes foresight and attacks out of turn. JKL and Cal are the only damage dealers on that team. Unless you have Zealous Ambition disks, then Yoda would be a good damage dealer as well.
Again, booming voice is going to hurt you more than help against Traya. I should have clarified when I said don't use mass assists, I meant take off booming voice. That is why your health goes down to 0 after the 1st turn, everyone assisting is taking big bites out of your health.
If you get all the sabers down in one or two turns (to avoid her hitting you), she will become toppled and you can do some good damage before she stands up, but it doesn't take long for her to get up.