It seems the enemy will only use the skill at the top of the list. For example, I could not get the Goblin to use Body Slam until I put it as the top skill. Also, Gnome won't heal even when they or their allies are at low health. I haven't tried AI controlled actors.
I did some more testing and other enemies still had the same problem. I honestly don't know if I fixed the first instance, in retrospect- I just had to work around it.