Bastila 4*??

To explain - CLS, Ventress and Finn would get me HAAT viable with my current line ups.

Don't use a zeta on Finn solely for haat, asajj rampage and CLS IBAT nets you a haat solo from around 20% remaining in p2.

If your shard is infested with zEP teams and your jedi are up to the task, then it could be worth it. I run zBastila / zGMY / zEzra / GK / zHoda and non-Traya zEP leads are full auto battles. With Traya under zEP I make sure she dies after Thrawn. Traya leads with Trooper can be a challenge depending on how well modded the opposition is, but DN in place of GK handles that easily enough (unless there's a seven star super fast Nest, which is still possible, but not as easy).

I've run zEP teams and the RNG associated with mirrors in maddening. zBastila trades that discomfort for having a harder time with Traya leads.

My Jedi team wouldn’t be as strong as that....
Bastila(l), Ezra, Old Ben, Barriss and GMY
No Zetas yet.
I only have 2 Zetas right now on EP and Thrawn. IBAT will be done tonight unless I do Bastila

I will be able to increase the rate i get Zetas soon as I’ve farmed everything I want from the ship store except a few more Bistan U-Wing shards and Sunfac. My Rebel Team can place top 50 consistently so 1300/day - 9100/week = 4 Zetas mats extra/week with a few left over....

I run a 3* bastilla in my arena, my team is zBastilla, gmy, Hoda, Ezra, gk. They have no problem taking me to top 20 it's just the traya leads I have trouble with. Otherwise bastilla lead zeta is absolutely amazing and I fully recommend it. In my opinion, arena is where you get the most crystals and should be your main priority.... My vote is bastilla zeta

With only Bastilla zeta'd I'm doing really well in my shard against zzpalp teams. Running

Bastilla G11, 4* Lead Zeta
Old Ben G10
Ezra G11
GMY G12
GK G11 (one piece from g12) 6*

This team kills 7* G12 Sion before he has a chance to go. The ZETA is more important than anything else, because an opponent's vader is going to be super fast, and those dots, resultant turn meter, and effect on zpalp's lead are the key. *none* of the dots stick with Bastilla's zeta.

First turn, Bastilla buffs/calls to assist GMY.
GMY does AOE (grants 100 TM)
GMY buffs full team
Ezra Calls GMY to assist (grants him 40% TM)
Old Ben Ability blocks enemy team
GMY uses special (Sion is sometimes already dead by here)
GK calls all (sion is definitely dead, and if not, EP is almost dead from the attack)

It goes this way every battle.