Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB - Early 2016 Australian 86 GTS head unit wiring

Hi all. I've been lurking this forum for a while but this is my first post.

I bought this car 2nd hand and have started doing various upgrades to it.

I'm currently working on installing an aftermarket head unit in my early MY16 86 GTS (Australian model) and I've found some interesting things with the wiring that I'm hoping I can get some help with.

The factory head unit is a PZQ60-537 and when I pulled it out I found an adapter Y-harness between the car wiring and the head unit that basically swapped a few wiring positions around and made it so a bunch of wires wouldn't be connected to the head unit. There also appear to be a few wires on the Y-harness that don't connect to anything coming from the vehicle.

With the Y-harness, the plug that has only 1 red wire in it connects to the head unit next to the GPS.

Here is the factory head unit:
Attachment 219494

Here is the Y-harness:
Attachment 219495

I also found the rear view camera to be connected to the head unit on its own 4 pin connector. I pulled a bit of the insulation back from this connector and found 2 of the wires (white and black) are connected together on the cable shield and it has a yellow and red wire. I'm assuming the red and yellow wires are the video signal and the white/black connected to the shield is ground, but I'd like for someone to confirm this.

Photos of the rear view camera cable:
Attachment 219496

Attachment 219497

I'm hoping I can get some help with figuring out the pin outs for the harnesses straight from the vehicle.

Ideally, if I could get a pin out from the factory head unit, that would be awesome. I have found one for the PZQ60-000535, but it says some of the ports are not used, when they are used on my head unit.