If you want to be prepared for the heroic sith raid, here are the zetas I’d recommend per team. I don’t know which zetas or teams you have, but this will give a good idea of what will help in the sith raid specifically:
For Resistance (phase 1): JTR lead & Insight, both BB-8, both R2-D2
For Jedi (phase 2): GM Yoda special, Hermit Yoda special, Ezra or Jolee special (depending on team composition), Revan all (if used)
For Phoenix (phase 2): all 5 available zetas
For Chex Mix (phase 3): Han needed, Chewie Loyal Friend helpful
For Aurra Hunters (phase 3): Aurra both, Boba helpful
For Deathstorm Nightsisters (phase 3): Talzin lead, Ventress unique, Daka
For Nightsisters (phase 4): Ventress both, Talzin unique helpful