Wiring Head unit question

[NJ C10 Guy]

OK, I think I have this figured out, and it should be easy, but the PO did a hack job on the wiring harness. Here is what I will be running:

- Kenwood Double DIN
- (2) 3.5" in the dash powered through the head unit

- MTX 4 channel amp
- 6.5" components powered by the amp
- 6x9s powered by the amp

- MA Audio 1 channel amp
- 10" sub

Now, the wiring should be as follows from the head unit (Kenwood's colors first) to the existing wires in the truck, correct? I'll be running new front speaker wires so I know what they will be and where they go.

- Black (ground) wire - Black wire in cab
- Red (ignition) wire - Yellow wire
- Yellow (battery) wire - Orange wire
- Blue/White stripe (Power control wire) - Remote input on amp

The orange wire is coming off of the courtesy lamp at the lower part of the dash. I thought this was hooked up straight to the battery since I can turn on the courtesy light when the truck is off so it should be good to use for memory, clock, etc., right?

Also, it's ok to cap off the gray wire, correct?