like others have said, not much benefit from a well set up disc/drum set up on a street car.
but in terms of path of least resistance dr. diff is the way to go.
i'd pop for this kit:
Mopar 10.7" Rear Disc Brake Kit
it checks all the boxes: compatible with 14" wheels, can use tapered or green bearings, integral parking brake, option for p-brake cables for a few bucks more.