Do 32u4's not work with this? (Pro Micro)

You need SLIPSerial.begin(115200); to start communication. In your code it is commented.
Did you use Nomad or a console?

I uncommented that line, and it still did not pick it up. I used nomad, as I have no console to test on at the moment.

Try to uncomment all the other lines, like on the original. I worked with an micro some years ago and I know that the board works with nomad, but not with console.

Still nothing. The diagnostics tab only shows EtcUsbDiscovery finding two devices upon plugging in the device. For clarification, I tried the USBtest sketch from the original repository, and even it did not show a connection to Nomad.

The strange part is that this board is just a smaller version of the Leonardo, even appearing as one in the Arduino IDE, and that board is confirmed to work in the CNMAT/OSC repo.

Still nothing. The diagnostics tab only shows EtcUsbDiscovery finding two devices upon plugging in the device. For clarification, I tried the USBtest sketch from the original repository, and even it did not show a connection to Nomad.

The strange part is that this board is just a smaller version of the Leonardo, even appearing as one in the Arduino IDE, and that board is confirmed to work in the CNMAT/OSC repo.

In general only Arduino UNO and MEGA are official supported, all other boards are maybe and depends on the OS and if there is a need of extra drivers. For increase power you should use a Teensy 3.x. The only difference between an UNO and a Micro is that the Micro have two pins (0, 1) more available and 500 Bytes more RAM.