I got some penetrating oil, and removed the snubber, but the rear wheel still refused to budge; I prevailed upon my local Buy Nothing group for a 3-prong puller, and a neighbor who wrenches occasionally can’t to the rescue! We got the wheel off, but left a bearing behind, which came off with a bit of fiddling and prying with flathead screwdrivers. I hit my local REI, and they gladly removed the freewheel, which cleared the way for me to attach it to the new wheel and reassemble the whole thing today!
The 16s with Tannus tires feel a bit different - a little twitchier, and I can definitely sense the way the airless tires absorb more force than pneumatic ones. Luckily, I don’t usually go too far on this bike, since it’s job is my short commute and multimodal trips.
Thanks for all the help and encouragement!