Huge breakthrough: all the hardware, except for one motor coupler, is installed; and I got the motor controllers configured enough to spin the motors. All 3 axes.

This is huge; I have some fiddling around to get the thing moving predictably and smoothly, and to install some movement limiters so it doesn’t self destruct– but in another couple of weeks of fooling around, I should be able to start making test cuts on scrap lumber.