My group managed to complete Sanity's Edge trial (on Normal) last night with only 3 people plus companions.
The companions (all healers) did pretty well but now I want to min-max our companion builds for better companion survivability.
I saw this other thread which has lots of great information, but it doesn't have an exhaustive list of companion skills that can affect other companions...
https://forums.elderscrollsonline.com/en/discussion/620245/
In particular, I'm most curious about the Restoration Staff skills...
Rejuvenation and
Mystic Fortress ...but if anyone has tested other companion skills, I'd be curious to know what works and what doesn't.
I play on PS4 so I don't have access combat logs or anything that would allow me to test this sort of thing.