to answer the first question: Iodine receptors are present in all cells of your body. but toxins (e.g., bromide, chloride, fluoride, mercury) occupy these receptors, displacing the iodine, which is one of the causes of Iodine deficiency.
add Iodine supplementation to the mix, and the iodine 'pushes' the mercury (and other toxins) out of those receptors. with two drops of Lugols on the weekend, you aren't going to do much in the way of displacing toxins in the iodine receptors.
i don't know enough about candida to chime in on the second question though.