I found the decoding book was not that great. The most useful and free was a Charger site decoding section.
You can use the internet to find out most of the codes. Just search around.
Your car has the map light so it may have had the A01 Light Group.
I recently watched an old re-run of Overhaulin were they did a ladies Barracuda Gran Coupe that had been purchased new by her Grandma.
It must have had cruise originally because I noticed the distinctive turn signal lever while they were stripping the car down.
You probably already know this the factory service manual has a section on the speed control.
There may be something in there that may help.
Accessories section.
It is most likely a fairly rare option and no one knows anything.
I have never seen a car with the original set-up only seen pictures in a book.
I would contact one of the known guys that does the top end resto work as I suspect parts will be pretty hard to get. They may know somebody.
I would keep the 195 thermostat for now.
I think the on/off spread of your fan stat is too wide and the location is probably not right either.
I have a similar radiator/fan combo to you - description wise anyway. I have a switch that is ON at 203F and OFF at 194F mounted in the intake manifold...
A recovery cap has a little flap valve right in the middle at the bottom of the cap were the water is.
You can pull it up with your finger nail.
A non recovery cap won't have this. The additional valve is the only difference between the two styles of cap.
Run the water level around 1 inch down...
You may already have a recovery cap. Plenty of info on the internet.
Recovery bottle and the correct cap and it will work. It is a good idea to fit this system.
It does take a bit of "effort" to get the switch in to this position.
The interior lights are ON permanently with the switch in this position - so you would not want it to be to easy and you may not notice the lights ON and flatten the battery.
I believe the first question you need to ask yourself is do I have the skills and perseverance to get this car going.
If not just go and by a nice one that you can just drive.
The tail lights usually go to ground through the tail light housings and the body shell.
When you were working on the coil did you disturb one of the ground cables under the hood?
These ground cables complete the circuit to the battery.
With the stall you have it is going to get up to the RPM were the larger header is no real issue - more of an advantage in the upper RPM range anyway most likely.
I found exhaust diameter was critical playing around with 750 CC motorbike engines.
The smaller the engine the more critical sizing...