I had some free time today so I remapped the USB ports.
I realise the dsl file in post #1 is not accurate (m.2 bluetooth USB port is actually HS07, not HS14; HS09 and HS10 should be USB2 only - "UsbConnector" : 0 instead of 3, etc...). Maybe that's your old draft? I've attached my version here.
Also, I find out that the two red USB ports (3.1 gen 2) are not under XHC@14. They are under RP05@1C,4
Top port:
USB3: PRT1: 01 00 00 00
USB2: PRT3: 03 00 00 00
Bottom port:
USB3: PRT2: 02 00 00 00
USB2: PRT4: 04 00 00 00
I'm not sure the red ports should be counted towards the 15, giving that it's controlled by a different chipset: