Vitamin C and other antioxidants will neutralize Miracle-Mineral-Supplement depending on how much and how close you take them to it
So it's best to take all supplements well away from Miracle-Mineral-Supplement
MMS won't make you deficient in Iodine but extra Iodine is beneficial,
Iodine is also an oxidant so it isn't affected by Miracle-Mineral-Supplement as far as I know but when it's converted to Iodide then it's an antioxidant so I don't think we really know how much effect taking a lot of Iodine has on MMS, I know some have taken them together with good results though not at the same time.