Ok, so it does look like the AUCs show up without power to the miner.
[...]
(Note: I have two AUCs, one is the newer one from an A741 and one is from an A6, connected to this Pi)
So you should at least see the AUC, even if you don't have the right power for the miner
wavelengthsf, thanks so much for taking the time to test this.
So at this point, with an AUC3 connected to the Pi but not visible in the cgminer status, I know I have either a bad AUC3 or bad USB cable/connection between the Pi and the AUC3. Too bad it doesn't show up in the Avalon 7 firmware.
Now, if Canaan would get back to my support request, that would be helpful. I think most of China is off till the 9th October due to national holiday so I guess I'll have to sit tight and be patient!