You can easily take zinc and copper to supplement anything that may be lost through chelation. PHT is a known danger in thal intermedia and major. I suspect from reported symptoms, that mild PHT is also common among older thal minors. As thals have reached higher ages, this has become more apparent as PHT and heart failure are found in thal majors with low iron loads. Precautions to avoid nitric oxide depletion and oxidation should be part of the thal regimen. These include supplements like L-arginine etc, vitamin E and magnesium. Letting Hb drop below 9 is not a good strategy, especially with your iron under control. There is a lot more to it than bone growth, your own quality of life being a main reason to stay above 9.
Treatment for thalassemia has advanced greatly over the past 10-15 years, as doctors begin to understand which strategies work best in maintaining health and quality of life. All doctors involved in treating thalassemia need to keep up on these advances, because too often we see patients know far more about treatment than their own doctors.