It really depends on what the child is taking. If the vitamin E is natural and not synthetic, 200 IU is fine. If it is synthetic, throw it out and find natural E.
If the child is taking folic acid and not folate, the dosing should not be high, as folic acid can build in the body due to its slow processing by the liver. If the child takes folate, a dose of 1-2 mg daily is sufficient. If it's folic acid, no more than 400 mcg should be taken daily.
Chelation is mandatory for transfusing patients. Iron will damage the organs if not removed. If the iron load is under control, lower doses of the chelator can be used.