No I don't think it would be a 1:1 mapping - you'd only get that on equal length arms where the camber doesn't change
With the measurements from the various joints, it could be calculated... But it's probably quicker to just do it!!
Yes negative camber does have its advantages in some cases, and it will affect the handling of the car - excessive negative camber on the front will change steering weight and self-centering characteristics - again the design means that the camber does change as you turn the wheel, and as the suspension moves up and down.
A VR-4 set up to factory specs does drive and ride fantastically - Mitsubishi did a good job IMO, changing this might change the way out feels, but it might lose some of the refinement if it becomes a bit more "lively"
I set my mum's old MX5 up with quite an aggressive geometry - it turned in and handled brilliantly and gripped well, but when it reached the limit, it went. Whereas as standard, it was slightly less responsive (but still very good) but it was a lot more progressive.
A VR-4 is likely to be at higher speeds when the limit is approaching - I'd rather it be progressive than snappy!
Suspension geometry is an art form, there's no doubt about that!!