Your suggestions are the same as the one I use when talking to kayakers about fishing in the winter months. The liner sock is one of the most over-looked items, and made my winters on the water enjoyable. The tough part, however, was finding them. Hard to believe that places like REI, Patagonia, The North Face and other "outdoor" stores may not have them on the shelves, even in winter months. I started with "running" socks from a local running store, as they were very similar.
@ The Nothing, Not sure where you are located, and as much as I hate plugging box stores, Dick"s Sporting Goods has the WigWam Gobi liner which I use and recommend. I work there part-time and we will occasionally run out of them, but that is rare.@ Tailing Loop, Great article and dead on!! I can really second the good fitting boots, struggled for a few years with boots that were a little too snug and never lasted long in winter fishing.JH