1969 valiant with 13 inch wheels

What you have is a 5 bolt 4.0" diameter bolt circle with 7/16" threaded lug studs.

Typically the left hand side (drivers side) of the car had left hand threaded lug nuts (reverse thread) if it still has those and your planning on keeping this (small diameter) bolt pattern, I recommend you replace the LH threaded studs and nuts. These are nothing but trouble.

When you say disc brakes all around, are you talking about 4 wheel discs? If so, why? What are the final intentions for the car? Most times a proper adjusted rear drum setup along with front discs is just fine.

I will let others chime in with the rest.