Noticed one more thing, then I'm ready to move to the adult: let's make the family organization (1-4 plus 1-4 ogre magi and 1 adult silat). Also, just noticed, in the third to last paragraph of the flavor text, it should be "monstrous feet" instead of "monstrous feat."
Damage is the same, so I'd assume Str is unchanged.
Height is 12-15' tall, which is still within the Large size range.
Spell resistance is better (55%).
Once silats reach adulthood (one to five centuries old), they can fully polymorph self at will. In addition, adult silats can cast polymorph other three times/day.
Yup, 3/day, CL 9? Not much else to do. We need one more feat. Deceitful would be the cheap one, but not nearly so effective as Multiattack would be. We can put 2 more ranks in each skill and go with Knowledge (any two) if we stick to Int 14.
Edit: Seems like we should also improve natural armor to +11.