sacredpath, thanks! No resolution just yet, but I’ve been away for a few days and am just getting back to it. I’ll take a look at how your snippet changes things once I have a moment — it might be enough of a change that the following is moot. ??
The aesthetic I was hoping to achieve is visible on the wordpress.com page for the Sela theme here: https://theme.files.wordpress.com/2014/12/sela-gravatrprofile.png
One of the goals was definitely to make the icon a little smaller, but the styling on the avatar, the bio info, and the various links shown in the image link above is exactly what I’m aiming for, and the CSS for it should be in Sela somewhere (the page reads: “As a bonus, Sela comes with a special design for the Milestone and Gravatar Profile widgets”), but something’s preventing it from being applied to the gravatar widget automatically.