In time for the last couple days of the event, I thought I might post my team and experience with beating the seventh tier of Artist of War. To start, this was the minimalist team I brought: https://swgoh.gg/p/193492485/characters/?f=Phoenix

I don't show this to brag, so much as to show that you can beat this event with garbage gear and a lot of luck. After about two dozen attempts, I cleared a 7* Thrawn. I found the strategy that worked for me was this:

• As many have stated before, the first targets that you should be concerned with are the Death Troopers. Save your Flourish (Ezra) and Metal Menace (Chopper) for removing taunt from the Stormtrooper.
• I have seen many suggest that you should always target Zeb as an assist, when using either Watch and Learn (Ezra) or Play to Strengths (Hera); to help stun and control the enemy targets. I found this did not work well enough for me, while the Death Troopers still lived. Instead, I chose to focus on tagging in Hera with Watch and Learn (For the meter gain) then choosing Ezra as the target for Play to Strengths. This makes quick work of the Death Troopers. Of course, if either Hera or Ezra is dazed, Zeb is a great fallback plan.
• Healing. You don't really have it. You will spend half the fight with a no healing debuff, so the passive healing the team is more or less known for is not there (barring some very nice tenacity saves). As a result, your "healing" comes in the form of Zeb and Kanan. Utilizing Honor Guard (Zeb) and Total Defense (Kanan) as pseudo heals until the Death Troopers are dealt with is about as good as it gets. Just be mindful of whether or not both Death Troopers have used their grenades or not, as they can remove buffs with them.
• Controlling Thrawn's Fracture is another aspect of the fight that helps a lot. In my attempts, I found it to be a 50/50 shot whether Thrawn would open with Fracture or Grand Admiral's Command. If I was fortunate enough to see him use the Command first, I would know Fracture would most likely be his next attack. I would direct the attack to a target of my choosing, in order to spare Zeb, Hera and Ezra (Since whenever they got hit by it, I would always lose quick). Usually I would use Chopper to absorb the hit, and preemptively place the Backup Plan (Hera) onto him.
• Once the Death Troopers are down, you move onto the next phase of the battle: Control. This is when I found using Zeb to stun targets to be the most effective. Still utilize Honor Guard as needed, but otherwise he is on stun duty. This makes him your most valuable unit in the second half of the fight, as Thrawn could still easily kill your units just on the back of repeated counters/Fracture.

All in all, this was what allowed me to unlock a 7* Thrawn, with minimalist gear and only being player level 77. I am not saying this guide is gospel, or that anyone can win using it, as luck played a huge roll in my victory. That said, it may help someone. Best of luck to all. Hope you unlock your 7* Thrawn and use him to go fist fight a Rancor or something. :P