The higher HbA2 level does indicate thalassemia trait (although this can also indicate sickle cell, but family history rules that out in this case, I believe). So yes, most likely thal minor with the low MCV also an indicator.
The ferritin reading can vary from test to test, so I would suggest another test after some months to see if this is constant. Iron fortified cereals are often used at this age and are probably a good idea right now. Iron deficiency anemia is not necessarily a lifetime condition, so further tests would be required after some attempt to raise iron levels with diet and possibly supplements if other tests indicate a serious iron deficiency (doubtful because of the fairly normal Hb level). The low ferritin being accompanied by a normal Hb most likely means that tissue iron is at the least, close to normal.
I know Marientina has an ongoing battle with iron deficiency so yes, it can be a long term problem in minors, but at this age and with the normal Hb, there is nothing to indicate that iron deficiency anemia will be a major problem here.
HbA2 is one of the normal hemoglobins and it does carry oxygen, but its levels are usually not significant. It consists of two alpha chains and two delta chains. An HbA2 of 6.5% in a patient with an Hb of 11.5 means that only .75 grams/dl is HbA2. Hardly enough to make a large difference. It is higher in thal because there are more alpha chains than beta chains, and they can combine with the small amount of delta chains available, causing a higher percentage of HbA2 among thal carriers.