I remember those monitors, but I forget what resolution they were. For what it's worth, Toy Story was rendered at 1536 x 922. I believe they re-rendered the whole thing from the RIB files for the bluray release.
Yes, there have been a couple re-render the whole thing. There was a good write up somewhere that I cannot find now where there was a discussion of keeping RenderMan bug compatible with the original or not. They also upped the shading rate and a few other quality knobs.