My daughter was diagnosed with non-classic CAH at age 3.  Turns out she is a slight salt-waster after all.  She also had the advanced bone age - and secondary precocious puberty.  Along with all of this, she had GERD.  She has been treated with Cortef and Florinef for her CAH ever since she was diagnosed and several different medications for the GERD.  She is currently on 40 mg of Nexium which works much better.  In addition, her gastroenterologist has said she can take over the counter acid medications as needed.  I would worry about not treating the CAH.  My daughter has had 3 crises in her lifetime and there have been other times when she had to be given an oral "stress" dose of medication for the CAH.  Maybe your endocrinologist and gastroenterologist would work together to find the right combination of medications that she can tolerate.