Additional parts needed for 77 Volare disc brakes conversion to 70 Dart Kelsey Hayes disc. ??

I've swapped my 68 front drum brake dart to brakes from a 73 duster, and caliper brackets and rotors from a late 70s Monaco. I gained BBP brakes and the large 11.75" rotors.
I needed new upper control arms for the large ball joint (I had stock style that needed rebuilding but decided to go with QA1 tubular) The obvious parts (which I'm assuming you have but dont know what you have) Knuckles, rotors, calipers, flexible brake lines, caliper brackets, lower ball joints
When I was down there I replaced both the pitman arm and idler arm as well because you've already done half the work by the time you disconnect the knuckles. As well as rebuild my lower control arms. I did the additional and completely optional step of welding reinforcement plates to the bottom of the lower control arms for peace of mind.
Since you're going from disk to disk, you shouldn't NEED to change out any other contributing parts if they were all functioning well (master cylinder, distribution block, lines, etc...)