This morning I was able to remove 3 of the 4 brass thread nuts. The
last was stubborn. After further freezing, I got the 4th off. Only
things I used were WD40, Ballistol, and freezing.

The wheels are not pop-in, they have threaded steel shafts.
https://www.dropbox.com/s/iku0193rzc...%20PM.jpg?dl=0