Getting started to work on my 1974 Dart Sport. I got questions

Hello Fellas.

Long time lurker. Long time owner of a 1974 Dart Sport (Pictured below)

1726767182477.png

Alittle about me. I grew up with my father who forged me into a Mopar or Nocar guy. Father purchased this car 25 years ago and had some fun in it until I was able to buy a house with a garage where it sat for over a decade. I work as an IT guy. Im new to working on mechanicle bits on a vehicle but not unfamiliar with mechanicle bits. Most importanty, not afraid of working on mechanicle bits.

Known problems:
No brakes (probably a leak, that's first on my list)
Engine idles bad and it leaks oil. Sluggish when revving. (It was raced before my dad had it. My dad did not change anything on it while he owned it)
Automatic transmission some times doesn't engage park and it shifts hard. (Shift kit for racing?)
Interior is smelly and it looks like mildew or mold on some places
Front bucket seats done match. I think the Driver was replaced with something very simular
Speedometer doesn't work.
Dad replaced the one exhaust pipe with pipe welded to together - would like to replace
Rear end squats to low. (Suspension is tired?)
Geared too low. RPMs too high at 60mph
Cosmetic issues but that will be in time

I don't have many people (or if any) to ask for ideas or recommendations. I have questions.

After the breaks are functional, I plan on pulling the motor to send it out for someone to go through it. I'm hoping to have it out this winter. I always wanted a 4 speed car. I looked up what I would need for parts and how to go about the process. My question is for those who have done 4 speed conversions. Am I over my head? Should I have the Automatic gone through and just be happy I have a cool car?

Im about dig into it. Any tips? Tricks? Recommendations?