I got time last night to assemble one of the two kits from @Defragster. And it's working great! Thanks @Frank B and @Defragster!
I compiled with Arduino 1.8.5 and Teensyduino 1.42. I had to comment out the println statements that were noted above. I could not find what was supposed to signal...
I am using this USB C to USB A female adapter with a PC motherboard Thunderbolt/USB C connector. It works with Teensy and other USB devices that I have. https://www.amazon.com/gp/product/B00Y1I1DT4