Removing the Default Theme
At this point, I feel I have the theming and functionality of hugo pretty well in hand. So I'll delete the "Blank" theme that I started with, remove references to it from Config.toml and .gitmodules, and see what breaks. Looks like it's just the "pagination" partial, which I'm using to drive the list page layouts. I'll just copy the pagination.html partial back in from the blank theme and... we're now theme-free! It's all natural jeffcode at this point.
I'll also add a favicon to the site to it shows up nicely in the user's browser tabs. Tutsplus has a nice tutorial on creating favicons in Affinity Designer; combined with facivon.io, the process of creating a basic favicon was very quick. Then adding a quick
<link rel="icon" href="/favicon.ico?v=2">
to the baseof.html template forces the cached favicon to be refreshed on page load.