Hi, Liz. The reports coming to this board on the Raplh Lauren suede paint have not been good. Many people seem to have problems with it. Also, paint it over so many types of surfaces alone would seem to cause it to still appear "patchwork". I would think that you might want a paint that would unify all the different wall surfaces. But then again, my local paint store will not let me buy paint unless I have a female with me. LOL
As for the surfaces in your den, is the fireplace real white brick or has it already been painted? If it hasn't been painted, most of us on this board kind of strongly suggest that painting brick is not a good idea. It may or may not be possible to paint over the paneling. Some paneling is not really wood but a picture of wood on mylar glued to thin plywood. Other paneling is OK to paint with sanding and a couple of coats of a primer/sealer. I would suggest that you consider removing the paneling and patching the nail holes instead. For the wallpapered section, you definately want to strip the paper off before painting. Let us know if you have specific questions after you consider this.