Admittedly, I've never played a Poko Priest, so excuse my ignorance if you can, but as I see it, a pet like system such as that from World of Warcraft would be ideal. To clarify, this would imply 2 major concepts, as I see it:
1) Players can manually use pet abilities, but also select 1 pet skill for it to automatically use whenever it comes off CD. The chosen ability should be clearly identifiable (make it glow or give is a shiny border). Limiting the automation to just 1 ability could be the right way to go as it prevents the pet from being fully automated and just being a "summon and forget" thing.
2) The pet abilities should be able to be hotbound. I don't know if they already are, but there should be a way to use the abilities through a keyboard button, either through traditionally dragging and dropping them onto your normal bars, or adding a section to the controls specifically for pet abilities.