I have kept an 83 wagoneer with a 3B engine for years before my Hilux.
It was all original, but then we changed the 3 speed gear with a 5 speed gear.
The parts that you have mentioned are not a big issue. Just check what differentials it runs with and whether they sync perfect with the 2B.
As for a 2B in that machine, I don't think that it would be an issue, but would also suggest not to expect too much out of it.
Does this one have a power steering ?
All in all, it is a hassle to maintain once things start to go bad and when one starts to do alterations, the whole geometry, chemistry and physics start to go bad.