To help you get started on this project; starting with the brakes, if it where me I would also go with power brakes, but would change out the fronts to disc brakes. I will include a list of donor cars that will fit your Nova. The swap is pretty easy to do. As for the power booster, you probably can use the later model, but you also will need the master cylinder and the porportioning valve and lines. As for the air, Iwould recommened an aftermarket set-up that mounts under your dash, not to say that you couldn't add the factory set-up, but it would have to be from a 71-72 like yours to get all the parts, hoses, lines, fittings, etc. Also all the ducting and outlets for the dash. I don't think the hassle is worth it. And if you don't like the sunroof, it can be removed and filled in to stock condition with the right body man. I did it to my 68 Chevelle. Well good luck with you project.
Donor Cars:
All Gm products from 69 to 72 i.e. Buick; Century, Skylark, Special, GS and a few to 74
Chevrolet; 69 Camaro
69-72 Chevelle, El Camino, Malibu
69-74 Chevy II, Nova, Concourse
Oldsmobile; 69-72 Cutlass, F85, 442, Vista Cruiser
73-74 Omega
Pontiac 69 Firebird,
69-72 Grand Prix, GTO, Lemans, Tempest, Grand Am
71-74 Phoenix, Ventura
GMC 60-74 Sprint, Cabalello
Hope this helps!