Well... the creation of the environment worked with "--updates-only".
However, my build requires a few things, one of which is libexpart1-dev
and that still fails:
The following packages have unmet dependencies:
libexpat1-dev : Depends: libexpat1 (= 2.1.0-7) but 2.1.0-7ubuntu0.16.04.3 is
to be
I found a workaround for this problem.
The core issue is that BY DEFAULT cowbuilder-dist (and pbuilder-dist)
will enable multiple "pockets", including "security", "updates", and
"proposed".
It looks like the "proposed" pocket (available here:
http://archive.ubuntu.com/ubuntu/dists/xenial-proposed
