Cha 14 sounds right.
What if we up the CL to 10 and give it Quicken SLA? (I'm still smarting from Paizo developer comments about Ability Focus. )
Plain old shortsword and shortbow?
That seems a bit much. If you're opposed to Ability Focus, let's at least go with a racial bonus. It's their one schtick.
I'm on-board with shortsword, but the bow feels "too martial" for these charmers. How about a light crossbow?
CR 1 or 2.
Treasure sounds right.
I'd go 3-4 HD (Medium), 6-8 HD (Large).
Jello's mostly water, like people, so 175-200 lb?
I'd like both single-type and mixed-type groupings of 2-8 or 12, but I don't have a good idea for a name!