Are the front suspensions the compatible for the 65 and 67 Barracuda?

Professor Fate summed it up pretty well. The only thing I'd add is that if you're putting in an aftermarket sway bar kit, they are typically designed around the assumption your car didn't have a sway bar to begin with, and include their own mounting hardware. So you'd only need to track down the early A body sway bar parts if you specifically want a factory sway bar.