I can go either way on Survival/Track. It doesn't specifiy whether they harvest specific souls, or simply acquire as many as they can. Since the rest of your feat selection is such a good fit, I'm inclined to just skip Survival/Track.
Updated.
Challenge Rating: 11? They are definitely superior to 9th-level human clerics, and seem comparable to the CR 11 hezrou.
Treasure: Standard (includes combat gear)?
Advancement: 10-18 HD (Medium): 19-27 HD (Large) or by character class (cleric)? This would allow for charuntes presumably created from giant clerics and other large humanoids, and allows for flexibility with caster level by stacking cleric levels.
A charuntes stands 5 to 6 feet tall and weighs 125 to 200 pounds?
Charuntes speak Abyssal, Common, and Infernal?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.