Installed my console yesterday. Everything went well. I don't have the three USB's up front working yet, but feel like I'm very close. I have successfully attached the USB cable from the HMI (behind the glove box) to the center console. On my 2015, I have the extra USB in the upper glove box. I disconnected it from the HMI (it's the USB with the green plug) and plugged in the new cable in its place. I used the cable recommended by TBarn (GM part 19303328.) You have to trim the connector on that cable quite a bit to make it fit in the HMI. If you are patient, it can be done and will still securely connect to the HMI. I then routed the cable to the center console.
I ran into a problem trying to get power to pins 4 and 6 on the USB. My local dealership didn't have any connectors (SAIT-A03GF-M064) in tray 27. I rummaged around and found something very similar from an old PC power supply that I was going to try and use, but they weren't a secure fit - too loose.
The way I installed the console was to remove the "new" console wiring harness, except for the wiring to the back cigarette lighter and the switch leg wiring for the light. I left that wiring in place, but cut out the remainder of the harness, leaving plenty of wire to splice. I then took the harness out of the "old" flip console. I spliced that old harness to the back cigarette lighter and the light circuit. Everything else on the back of the console is plug and play. I then used one of the cigarette plugs from the new harness to build a jumper for the second cigarette plug up front. Everything now works except for the power to the three USBs.
I woke up this morning and realized I think I have what I need to finish this. Because I pulled out most of the new console harness, I'm left with the plug from the 2 USB/SD/stereo plug. That plug is identical to the plug that connects on the back of the 3 USBs. So my next step is to cut that plug with plenty of excess wire and splice pins 4 and 6 to power and ground. My theory is that I will have fully functioning USBs up front once I do this. (The only minor downside is losing the USB in the upper glove box.)
I plan to give this a try one night this week. I'll report back.