Protection Circle mods on everyone, more protection mods on tanks.
Better for Expose as stated above this can occur on any character.
If you have Troopers under Veers Lead, they get protection % back per kill.
If you have a Thrawn, he restores protection.
if you have CLS he recovers protection.
If you Have Kylo Ren he recovers protection.
If you have Ewoks they can recover protection through Paplo's Don't hold back.
Zeta ST Han recovers % protection.
CHS restores protection if he heals you to full so you actually want less HP and more Protection for characters that are grouped with him, but he should have very High health and moderate protection himself cause his skills benefit from more health.
For the HATT raid you needs a lot of protection just to survive, dead characters do no damage.
Between GW nodes your characters recover some protection if they are full health.
If you don't have a healer in the group, protection will help more than health.