J.W.
Nutritional stuff including IgG food allergies and even blatant nutritional issues turned out to be important in both my children's DSM diagnoses. So were hormones! Yes even at that age, and I feel a bit angry that the original pediatric endocrinologist for my younger daughter did not catch that! (see http://itsnotmental.blogspot.com/2009/02/psychiatrist-vs-...)
Genova Diagnostics are a good, reputable laboratory. We actually uncovered a lot via SpectraCell labs a few years later.
As for the biofeedback... I don't know, but I do know that people have had huge success in "brain retraining." In Canada they consider it medical - I've read about a home device - This woman wrote a book about it: Train Your Brain, Transform Your Life: Conquer Attention Deficit Hyperactivity Disorder In 60 Days, Without Ritalin (http://www.amazon.com/gp/product/0615297943/ref=as_li_tf_...)