Hi Brenda,
Damp Heat can happen in any age animal, particularly if it is on a processed and/or carbohydrate-based food. It is the leading cause of hypoglycemia.
So, given that you need a Damp Heat formula that promotes peristalsis, relieves constipation, and promotes insulin sensitivity, I would think first of San Ren Tang. It should work, I think. BZYQT may be too tonifying for this kitten, but you are right...in young animals, the default diagnosis is Qi deficiency (which BZYQT treats), so this case is quite unusual. I would still trust your assessment, though, and treat on that basis.
Good luck!
Steve