Here, things that would make NPCs infinitely more useful:
1) Split Soothing Healer into two paths (RDM or WHM) or just remove all enfeebling magic besides Dia II.
2) Give the AI the option to take no action. If Dia II is on the monster and I have white HP and no status effects, it's cool with me if the NPC doesn't cast this time.
3) Prioritize Haste above all things.
4) I'd go with 3MP/tick Refresh for the NPC Fellow. The mage one isn't so helpful that I'd ever consider resting for him to get MP back, so he turns into a gimp melee fellow after 10 minutes.