Stefanie, you didn’t mention the OH-17P levels.  Low OH-17P levels, which indicates oversurpression, negatively affects growth.  Cortef, not florinef regulates OH-17P and a host of other things.  The target OH-17P range for CAH kids is between 500-1000 with blood draws taken in the early morning before meds.   High OH-17P readings causes the child grow quickly with bone age advancing rapidly and growth stopping early.   So, I mention this because I don’t understand the florinef adjustment which affects plasma renin. 

I have never heard of growth hormone for such a young child.  If your doc would take care of properly managing the CAH, the growth will take care of itself, in my humble opinion.