For the 1973-up disc brakes, you need the ball joints from the same years, so yes the 1976 parts are correct. K772, K781, and K783.
You can use the C-Body tie rod ends and sleeves, but this was the hot trick before the availability of solid adjusting sleeves. The main source of flex was in the sleeve, not the tie rod end, and the solid sleeves come close to eliminating flex. QA1 52325 sleeves are solid steel for the A-Body size tie rod ends. For all but serious road racing or autocross with big, sticky tires, this will do all you need. But, either should work, so your choice. Good luck!
1968 PLYMOUTH BARRACUDA QA1 52325 QA1 Heavy-Duty Tie Rod Sleeves | Summit Racing
