Aquavitro is owner by Seachem and is one of many brands that offers many products that may or may not be needed or effective in any given tank. I have heard that the 8.4 is a very effective buffer, but haven't really seen that the rest of the line is anything above and beyond other brands.
Ditto. Do not blindly add things, especially things like iodine.
I would love to see any half decent experiment showing that amino acids (building blocks of protein, which is easy to get), and other trace additives actually do anything.