Hope this helps...
The Alpine amp first:
1. Are you using a line out converter or are you cutting off the RCA plugs on the amp harness? I think the red=right channel and white=left channel still applies if you choose to cut off the plugs or T-Tap these.
2. I see your diagram that you have the amp to the A pillar. I wired my the door tweeters to the amp and then I T-tapped (because these are so much cheaper than post-taps and I figured it's not the car's original wiring) the speaker wire to power the A pillar speaker in parallel.
Sub:
The sub is a dual coil speaker so just wire the 2 positive and 2 negatives together to connect to the amp positive and negative output. I haven't done this yet because the amp I plan to use is sold out everywhere. I plan to use the Pioneer GM-A3702 in bridged mode because this appears to be the cheapest amp that can power it.
You should run separate grounds for each amp. But you may be able to power both amps with one fuse. The alpine is only 15A. I plan to eventually run both off one (Alpine is 15A and Pioneer is 25A).
Rear deck - looks correct. Video shows the locations of the wires, but not for the front ICE.
I did not tap into the front ICE for input so can't help you there.
@AdamMacDon Interested to see your video.