Bloody Pox, Entangling vines and devouring swarm are pretty good to proc most of your pet-devotion skills (like shepherd’s crook, mogdrogen’s howl and bysmiel’s bond) because they’re near 100% proc as they spread or tick many times. Note that either of these skills work best when there are a lot of enemies around though (the proc is not so high against single targets).
Regarding which devotion skills you link to your pets, I think it doesn’t matter that much as long as you grab most of the pet passive buffs. Assassin’s mark works well on the primal spirit (because of piercing damage), I like to use guardian’s gaze on the briarthorn because he uses AOE and sometimes procs a lot of eyes which do decent aoe damage.
I’ve used elemental storm for a long time, tried acid spray, whirlpool, falcon swoop, twin fangs, pretty much anything. In my opinion the skills that work best are the ones that debuff mobs (scorpion sting, eldritch fire, acid spray, assassin’s mark) because all of your summons benefit from it. The main source of damage after all is your pets, so it’s probably better to “optimize” them rather than add some extra raw damage on top of their damage.
The nerf to ancestor is pretty bad actually; I’m still using it because I can’t use another pet (not enough skill slots or devotion points) but it’s definitely not as good as before.