So, it turns out that I don't have a tool capable of cutting 5mm hardened steel rod. Admittedly, most of my tools are for electronics (or basic woodworking and home repair). I've got a family member nearby that will let me use his Dremel.
Otherwise, I've printed all the body elements required to make a functional skeleton of the open lidar. Once I get the rods cut to length I can retrofit my stepper motor and get the skeleton assembled. Really want to get the skeleton done. I still need to print lids and the battery box, but those won't stop the device from working.
I still need to finish the new schematic that uses the Teensy 3.5, but the Teensy has so darn many pins that you can practically throw a wire at it from across the room and be plugged into a pin that will work. That's going to make it a lot easier to get a good layout. I've looked at the schematic and it's going to be pretty easy to get a clean layout with the new circuit.