Again, in my chosen theme, Dynamiix, Layouts works on regular pages. It is only the custom page type that it does not work. In twentyfourteen exactly the same problem. How does this need to be debugged? The name of the file layout php for pages is pages-layouts.php. How in the world would the custom post type be named single-feed-pages.php That makes absolutely no sense at all .
I'm backing up and then will make the test env