Wow... maybe all the for sale posts should go through you first so people know what to sell their things for!? Sounds like you are full of great information and please keep posting.
Yes.. that will work.... But, well that will work. I have used so many line converters for installs and they work great! Although, I'm pretty loyal to http://www.davidnavone.com converters. They are a little expensive, but worth it.
Tap the 2 sets of wires coming off the line converter into the rear speaker outputs of the headunit. So right rear +, right rear -, left rear + and left rear-.
I call the red wire accessory(acc). Yes.. yellow to yellow and red to red. I would keep your friend away from your car or you will have a dead battery someplace. :cheers:
No.. that isn't how you do it. The power wire is constant from the battery and the red accessory should be wire to the ignition. If you bought a wiring harness then all the wires should be matched color to color. I'm pretty sure most wiring harnesses are color matched to aftermarket headunits...
You can use the factory. You will need to run speaker wire from the OEM wiring in the door or where every your speakers are. You should be able to pick up some wiring harenesses for the OEM wiring connected to the OEM speakers. The wiring harness would connect to the OEM speaker wire connector...