Eric, I'm not the one you really need to the answer those questions. Personally I'd be a little more of a stickler on the parts than Rob since the carbs may be available repopped from Holley (or service dated and much cheaper), and the manifolds are available if you look daily on e-bay.
edit: rules now say stamp # on carb doesn't need to be correct if the carb appears externally correct.
The carb is a bunch small so you might want to find a shop that can massage the insides to make it flow a bit (
like 900 cfm) better too. Heads are another story. If they are flat not available and another casting # offers no performance advantage an exception <u>might</u> be made.
Look here for the F.A.S.T. rules.
F.A.S.T. rules
Sign up over there if you want to ask the guys that have final say if you can run the parts you are asking about.
F.A.S.T Questions
The G70x14's are ok, and if a rear sway bar was available in 66 I don't think anyone is going to measure it. Front sway bar is optional.
Hope you can see your way to building a 66 SS car. Those coil spring cars can really hook and a 66 is the lightest one available with a big block except for a 65 Z-16.