No need to apologise, it usually takes me a few attempts to understand a new concept.
Question 1, you have already answered it yourself, plants do need N & P.
Question 2: I have not used sequestered iron other than on my blueberries, which require acid conditions. Most cypripediums require alkaline conditions, therefore I would not use it. Instead, I tend to put a little dolomite lime around the stems, they like that. And if the foliage gets too light in summer, I give them Epsom salts as prescribed on the packet.
All these items are available by googling on the web.