What would you pull off this C Body for your A Body???

Pull the entire drive train, including linkages. None of the suspension or steering components (except PS pump, and maybe tie rod adjusters) will fit the A body. Yes, the rear would have to be narrowed, along with the axles, spring perches moved, etc - probably a 8.75" one legger - and all that might be more trouble than it's worth. You should plan on upgrading the 7.25" rear though. Rear brake assemblies, rear e-brake cables. Grab the drive shaft (will have to be shortened) - if nothing else for the front slip yoke.

The 26" radiator may not fit between the frame rails without some trimming and you'll want to open up the core support to fully expose the radiator core. And that means your horns will have to be moved. Keep the shroud if it has one.

BBP spindles and upper control arm will have to come from somewhere else.

Nothing else comes to mind right off hand.