Sure, so I went into MusicBee - Edit Preferences - Devices, and removed the phone, then ran MusicBee Wifi Sync again and did a fresh sync. I get a few of these errors:

The strange thing, is that this is not one of the songs which I generated a .lrc file from, there's no such file either on my PC or phone as a result of the sync. Perhaps the mp3 has embedded lyrics in it. I got no similar error for any of the songs for which I generated external .lrc files for, and just like before there's no lyric files being synced at all.
This is what one of the PC folders look like with the lyric files outside of the mp3s:

EDIT: definitely embedded lyrics, I'm using Mp3Tag to remove them all right now, and am syncing the library now. Stay tuned
EDIT2: ok the sync completed, and I got a bunch of similar MIME type errors for the .lrc files that I had created external to the mp3s, like the following:

I got the above error for each .lrc file that I had created. Checking the device none of the .lrc files got transferred.