Having found the source of confusion, I went ahead and read the elisp for my airline theme which I probably should have done in the first place. This made it clear that I could load a regular theme first, and then load the airline theme after to get the best of both worlds. So, now I’m happily working with base16-irblack and airline-minimalist.
This all works great with my init.el available in both my Fedora and Debian TemplateVMs so any AppVM I spin in #QubesOS is a few seconds away from bliss