"Your Amazon USB dongle will work with FPP to control a DMX based DC controller. I doubt that it will output LOR protocol (though I'm willing to be proven wrong)."
I did not try to use the amazon usb to control the lor protocal but last year (2014) I was running xlights thru a pc hardwired to control an lor box ( I think I had it sequenced as dmx) and also a Renard ss24 (flashed to dmx protocol). Since I was new to xlights and was not set up with fpp, I did connect the lor rs485 to the lor box with a straight cat 5 and I used the amazon dongle to connect to the renard controller (which I know was flashed to dmx).
My sequences were done in lor and converted to xlights 3. The problem I has was at first I did not have the pinout data for the amazon dongle. It took a little research and I don't remember how I found it but when I found the data + data - and ground and wired the cat 5 crossover accordingly it worked. I set both up in xlights setup as open dmx. I don't remember all my exact setup but I did write it down and took pictures of the setup because I don't remember how I set up all the time. My brain is getting old.
I am very glad to go with xlights, fpp, f16v2 (connecting my renards and lor to the f16 via daisy chain) and its so much easier. Again I wrote everything down and took good pictures for this years set up. In the process of writing my own setup manual, especially since the network setup for me is a little out of my league. Thanks to all the help in this group, facebook folks, etc.