1. Yes
2. No. You do have to remove the outer bushing/seal but you may leave the inner bushing in place.
3. Yes, but I do not know what is the acceptable tolerance
I agree with olBlu49 - at a minimum.
You are doing a frame-off restoration. I would recommend a rebuild using a rear-end installation kit that most vendors sell with the 3.55 ring/pinion upgrade (I'd do the ring/pinion upgrade, too, but you could just use all the new bearings, bushings, and gaskets in the installation kit).
Tim
