Suggested Skill Ranks: Concentration 8, Diplomacy 8, Escape Artist 8, Hide 8, Knowledge (nature) 8, Move Silently 8, Sense Motive 8
Feats: Weapon Finesse and Improved Initiative (or Dodge and Mobility--they like to flee)
CR: 5? (Doens't the ability to cast spells as an Xth-level spellcaster usually require at least that CR?) Their other abilities don't really warrant a CR increase.
Weight: A jaguar is fairly comparable to a leopard which weighs 120 lbs. Since a chac resembles a "slender jaguar", this should work.
Chacs speak Common and Sylvan.
Caster level 10th for spell-likes?
Spells: Chacs can cast divine spells as 5th-level clerics. A chac has access to the following domains: Air and Water. The save DCs are Wisdom-based.
Typical Cleric Spells Prepared (5/4+1/2+1/1+1; save DC 11 + spell level): 0--create water, detect magic, detect poison, purify food and drink, read magic; 1st--bless water, entropic shield, obscuring mist*, sanctuary, summon monster I; 2nd--owl's wisdom, resist energy, wind wall*; 3rd--summon monster III, water breathing*.
*Domain spell. Domains: Air and Water.