The book that the map came from is copyrighted in the 1980s, and it looks like a hand-drawing, with a caption to the effect "approximate district locations." You probably know better than me, but if I were to use it, I think I'd have to judge if it's fair use or not. Plus, I was only sent one page from the book, so I'm still tracking how to properly give credit.
Regarding the other sites, I've spent a great deal of time looking through the various repositories of North Carolina maps, and I have not found a map that gives the districts I want to discover. There is at least one remaining, Captain Davis District. But I don't know what I don't know.
What I have learned is that some district names changed, and some district boundaries changed. If I want a rough approximation of where the districts were in 1820, 1830, etc, I can look at the current townships - when I overlay a township map from the current government web page with the hand-drawn 1850 map, there's a lot of overlap. I've more or less located where Michael Wall (referenced in the question) must have been, and it's probably a location that's consistent with four different district names, depending on which census year you look him up in. I've added this information to his profile in research notes.