Hi everyone from the proud owner of a 69 Dart

Welcome aboard!

I think pretty much all the '67-'76 a-body stuff is fairly compatible, but what specific parts are you looking to rob?

There's a forum for brakes here where you should be able to find threads that discuss the various disc brake swap options (Kelsey Hayes SBP, 73+ BBP, Scare Bird, etc.). There's also a forum that is focused on suspension. The search button is your friend!