Small changes in test results have no real relevance. Every test will show slightly different values for things like MCV and MCH. They will always be low in thal minors, as the bone marrow will always make small defective red cells, which causes the average volume to be lower, as seen in the MCV. If one is also iron deficient, they would see a slight increase in these values, but would still remain lower than normal once the iron deficiency is addressed.
I'm not convinced on the iron deficiency. I see far too many reports from thal minors, all showing iron values low, yet most don't respond to iron. Iron water, like Spatone, should be tried if other iron supplements haven't worked. It's a naturally occurring form of iron and is easily absorbed. It is much less harsh than other forms of iron. If that doesn't raise the Hb, it's very doubtful that iron deficiency is present. The RDW being high but not as high as would be expected in iron deficiency, IDA, where it's more likely if the RDW is above 18, also is more in line with thal minor than IDA.
Your B12 is at the low end of normal and doctors will say don't supplement. Thal minors do much better with a level near the high end of normal, >800.
The D is measured in different units, if it's low. Do you have the units of measurement that were used?
Hb >10 might be affected by folate and wheatgrass. Many minors do have Hb's in that range.