a) use after mapping - blog.gardeviance.org/2014/08/busine…
b) they're a more advanced SWOT, there's no real context
c) No, you can't simplify mapping - medium.com/wardleymaps/ke… - it is as simple as it can be whilst remaining a map.
Mapping is a total novice looking at a chessboard, realising there is a game and a lifetime of study.
Business model canvas is asking the question "Do you want to play or eat?"
Normal business is trying to eat the pieces or jab someone else with them.