IMO vit C does not mess up Iodine or anything else, unless you take too much of course.
From your list of doings, I may suggest to slow down; focus on Iodine for a while as it is a big enough challenge for a tired body. I did this mistake myself; tried to cover all bases at once; this really messed up everything!
Too much selenium vs the iodine, I hope you mean mcg not mg:)
Adding SSKI , yes; as the little dose of Iodine in the nacent is hardly enough to cover the daily requirement for the thyroid, not to mention breasts that want 5 mg, daily.