Newbie Here! Planning on building a CR

[Roylerumble]

Hello everyone, new to the forum. I'm from Edmonton, AB, Canada. I'm planning on buying a nearly complete kit that's been in an elderly friends possession for some time. It's never been started. My son is 7 and is showing an interest in building cars and I want to foster that. I'm not a novice in the garage, but my experience has been with muscle cars and doing most of my own repairs. I figured a kit would be a great place to start for my son, rather than a ton of fabrication or restoring something. Plus, I've always loved the Shelby Cobras, and I have a 91 Mustang 5.0/5 speed donor car, and because my son is showing interest, I don't have to convince my wife about it! A first for me! The build would be a mild street cruiser, nothing radical, but I'm sure that may evolve. I'd keep the 5.0 fairly stock with some bolt on upgrades.
I have a few questions, and I'd really appreciate and advice:

the car is an automatic kit, which I would want to change. I did find a thread hear on pedal upgrades. I guess what i'm asking is if this swap is difficult or can most of the parts be purchased off the shelf? Can a trans mount be easily found as well?

The original owner did buy a bunch of the add on kits, like the heater/defrost, but never received the heater box. Does anyone know if CR made their own box, or was it built buy another company, if so, any chance anyone knows the manufacturer and part no.?

Lastly, it's missing the roll bars and side pipes. I'm assuming any local shop could bend some pipes and a roll bar could be fabbed up, but could I buy these parts from a vendor, even though there were so many different manufacturers of kits?

That's my little guy helping replace the wheel bearing on Mom's Caddy.

Looking forward to the build, and learning from all the members here!