Arena team help?

With what you got, you may be stuck in arena. I would switch your focus to going after Revans or other journey characters before putting any more relics on, as you seem really top heavy. Based on some of your characters it seems like you might be going for SEE; that could help you in arena (though it's a months-long journey) but you will still not have a very rounded roster for the power increase you will have.

Keep focusing on SEE. Yes, you may have some trouble in squad arena currently, but you're quite close to being ready to unlock SEE. I would recommend to stay on course, keep gearing Sidious, Piett etc. and also put some gear on stock for when you actually unlock SEE. However, you may want to switch a few mods around on your current team. F.ex. Vader could use an offense or potency cross (try slicing the cross from Sith Assassin) and maybe an offense set and a CC/Potency set would be better than the current speed set and health set. Thrawn could use a speed set instead of his current CD set. Thrawn isn't really there for his damage. Just a few suggestions.