The only 71 Chargers with a manual choke were those equipped with a Hemi. You could probably use a reproduction Hemi choke cable assembly to work with that. The hole was only added in the firewall when the car had a Hemi, you just need to drill it open, the hole is the one to the left with the rubber grommet in the attached pic, your orange box is covering where yours should be. Most manual chokes used a swivel with a lock down screw in the end of the choke flap ear which allowed for a good hook up for the choke cable/wire. What you have there uses a cable end that has an "L" shaped end that goes through the small hole in the tip of the choke flap ear. You are correct, item #3 does not have anything to do with the choke cable.

*I'd recommend switching to an electric choke setup for a street car .02