I have 93ish cutlass leather rear seats in the back of my GP. As mentioned I put up a how-to in the junkyard thread.
As far as the buckets, I don't know how much of the rear panel between the trunk & cabin of the W body stays with the seats and how much stays with the car. There is a lot of exposed carpet and I'm not sure if that is going to retrofit or not.
The normal bench rear seat fits pretty smoothly and even has a passthrough which would be awesome for any G body (except a GP) because it has the additional bracing that makes the passthrough almost useless.
View attachment 205268