Parts Swap Between 69 and 75 Dart

I recently purchased a 75 Dart as a donor car for roof skin and some other miscellaneous parts for my 69 Dart project. I have a couple of questions. First, if the 75 Dart has an 8.75 rear in it, can that be direct swapped into my 69? Also (and this is not the exact right place for this question), if the 75 has disc brakes on the front, can all of those parts be direct swapped into my 69 to complete the front disc brake conversion?