This all looks complicated and unnecessary. Sure you got worries, but
are there good examples of such abuses taking place? Looking at
CPython documentation as an example, they do share same license as the
respective software they document... not much worry is waster on
dual-licensing and other ugly things. Same applies to Django
documentation (as well as the majority of FLOSS projects).
AFAIK, the only people doing the dual-licensing and non-libre docs are
those hoping on making money from said documentation/software. That's
not the case for Pyramid.