Thanks, everyone!
When I went back out it had seeped a teeny bit (1/2") of coolant from the reservoir. I also added about half a pint to the radiator. When I started it the temperature was still at 132F (it's about 20F outside), so maybe a good chilling overnight will cause it to contract a little more. No leaks anywhere, including the thermostat housing and the water pump I installed Saturday.
I'm just going to watch things and top off until things stabilize. For what it's worth, I got the bright idea of removing the bleeder setscrew with the radiator cap off, thinking I might get some trapped air out and top off again through the bleeder screw hole. When I did, there was no sign of bubbling but the coolant (still right around 130F) started slowly overflowing. I might have lost an ounce or two before I got the screw back in, but there wasn't any air there.
Just as a final kick in the pants, three days of starting the Jeep and running it only briefly, coupled with near-zero temperatures the last two nights, apparently did my battery in. I had to jump it twice before I deemed it roadworthy. I then went to the gym and needed a jump there as well. After I left the gym I drove around for an hour in the beginnings of our snowstorm (10" expected, with about 2" already on the ground), so hopefully it got charged enough to start tomorrow. Unfortunately, the previous owner did not bother to scrape off the Month/Year ovals on the battery sticker so I have no idea how old it is. I guess if it proves problematic I will rationalize a new one as part of my ongoing campaign to replace all the fluids, wiper blades, spark plugs, etc., so I know exactly what is in there and when it was last serviced. It never really ends, does it? :icon_lol: