You need to get the adapters that fit the 11.75" rotors. the M body ones are for 10.87" rotors.

You need the control arms, not sure on the lower ball joints, been a few years.

You can run 73 and up A body disc hoses is you mount the calipers like they are mounted on stock 73 and up disc A bodies, otherwise I use 79 F body hoses and remove the bracket.

Run the combination valve off the M body if it has the same diameter rear drums as your A body. The aftermarket adjustable valves are best used to fine tune stock proportioning, if needed. Some will tell you that they work just fine by themselves, those people know nothing about braking systems.