Don't complicate it, taking Iodine is as easy as taking any other mineral the body needs but isn't getting.
All of those "companion nutrients", are things that the body is supposed to be getting anyway. What happens is, typical person X wants to try iodine, and then they're confronted with the "companion nutrients" aspect. That is only because they weren't getting enough of those companion nutrients previously. Otherwise the companion nutrients would not be necessary.
In this way, the path that led you to Iodine is one which educates a person in many other ways. It makes you take other things you need anyways. PROPER Iodine SUPPLEMENTATION IS A HIGHLY EDUCATIONAL PROCESS !!
We're generally inquisitive creatures, its only natural you raise the issues and questions you did. I think you already know the answers, they are easy, try walking barefoot in the woods or along a watershore and ask these questions and the answer will probably come.
Meantime, don't sweat it. Take your time. Drinking lots of good water is never a bad idea.