Can you provide the history of the board. Is it new and never worked or did you use it in the past with success? If the latter, what was the last project that you worked on when it was still possible to upload; we might be specifically interested in the fact if there were (or now are) voltages involved different from the 5V and if anything related to motors, relays etc. were / are.
Your PC seems to be a Mac; I don't have experience with it.
The first question would be if that device disappears from the IDE when you disconnect the board. As it says Uno at the end and the VID/PID match the VID/PID of a genuine Uno I suspect that it will.
You can try the loopback test. I suspect that it will fail.
The second question is what your Mac thinks of your board. As I do not have experience with a Mac I can't tell you where to start digging but you might know; it would be somewhere in the system logs (under Linux it would be the dmesg command).
You did a bit of research by the looks of it 
Lots of useful details. The only thing that you have missed is the avrdude command that is issued by the IDE. If you enable verbose output dutring upload under file/preferences in the IDE and perform an upload the first few lines after the memory report will contain that information.