camber change ...varies as you don't know where the arms been...
You can easily just swap them and see before cutting (particularly easy w/coil overs).
...no bars/springs, you just need to check it/hold up the pan/car at ~the final ride height, assuming you know it.
Swap EVERYTHING ... brakes and all, just to test if you like.
It should be close... A LITTLE -camber is not a killer, but with those tires, much less could save $$$ quickly.
I'd be SO tempted to fab an Ariel Atom-ish swoopy tube frame to stick on that clean pan.
I'm delighted to see you are keeping the safe late seat hold down setup.
Any Mk1-3 (and maybe Mk4=?) VAG 2 door seat will work with minor rear support leg adjustment. (few whacks with a rubber mallet and some tweaks with a prypar to square up the sliders)... That means leather.. HEAT... etc are options.
Decent factory adjustable seats make for an incredible upgrade to a ACVW, at least from a drivers ass standpoint.
I'm running Corrado front sport seats in my square, the std Golf ones are a couple inches higher and may work better in a Bug.
You'd be surprised at the dimensions that cross over between the models...
the matching rear seat/arms/ side upholstery can be made to fit in a T3 (and IIRC a Ghia) remarkably well, might work on a Bug?