There are a few things I would add to that documentation, as well as one thing which seems to be a mistake — namely, talking about getting a grep result for FTDIKext.kext leading to the deletion of FTDIUSBSerialDriver.kext, which are different things, and (in my experience) both need to be removed in order to let AppleUSBFTDI.kext work properly.
Additionally, I think it’s worth mentioning that kexts can also be found in /Library/Extensions (not just /System/Library/Extensions), that “unloading” an extension is different to removing the file completely, and that serialosc devices initially working but then failing after being unplugged whilst still showing up in USB Prober is a symptom of conflicting FTDI drivers which people might not immediately notice and therefore should test for.
If that all sounds reasonable I can write up a pull request to the monome docs to incorporate this info.