Converting rear drum brakes from SBP to BBP

A lot of information to digest. I am beginning my build so let me make sure I have this right. I want to go to BBP just for the better options of wheels. For the front my option is to swap the front spindles, rotors and upper A arms from a 73-76 B body? that would have to include master cylinder and proportioning valve? which while I'm there I might as well get the booster (did I miss anything, like linkage)? Now for the rear I can use the axle from the same car but I need to relocate the spring mounts 1/2 inch inboard? If I just want to swap axle shafts I have to drill the drums for BBP? I can't swap drums and backing plates from the donor car and install BBP axles unless I use the axle housing from the donor car, right?