If I have a roster like this, who should I zeta first?

Hi there, just looking for advice on the below since I'm about to start accruing zeta material.

If I plan on mixing and matching the below roster, who should I zeta first as the lead? For clarity, I'm putting the highest emphasis on arena first, followed by GW and raids. All my toons are at gear X and near gear XI

Planned leaders (who should I choose to zeta first?)
Maul, Vader, Nihilus

Roster I plan (or potentially plan) to mix and match with the zeta leader

EP, Sid, Dooku, TFP, Shoretrooper, RG, Tarkin, Boba, QGJ, GS, Phasma, Kylo

Thanks in advance for any advice!