I put the arms in first. The I bolt the upper arms to the rear. Last ones are the lowers. It would be difficult to line the control arms up while bolted to the rear.
When penetrating oil and a drift (edited for auto incorrect) punch does not work on leaf springs fasteners, I have resorted to a recip. saw. If you can fit a blade in the bushing without cutting the car, that might be a final option.
I swapped a T-Bird Super coupe rear on my car awhile back. I did it by myself with beer power, took a weekend. Uppers first, then keep the axle on the Jack. Manipulate the Jack height to get the lowers in place.