Short side axle half shafts are interchangeable from 1968-up for 40, 55 and 60 series. (1967 and earlier are 10 spline, 1968-up are 30 spline). Long side vary, 40/55 are same same, 70 are a little wider but can be made to work, 60 are longer and 80 are longer yet. Interchangeability amongst birfields is as follows: Early to 1967 use ball and claw joint, not birfields. Few if any of our participants will be running these. 1968-1975 will use 10 spline birfs, again rare for our group, but I run them and carry spares. 1976-1978 will use long 27 spline birfs, which are also rare. These were the first disk front brake birfs. Most common are the shorter 27 spline mini/runner/cruiser birfs from 79-89. These can be used for the 76-78 applications with a large fender washer and M8x1.25 bolt because the circlip doesn't reach. 80 series only fit 0 series, they are much bigger than 40/55/60/70 series.
There are at least 4 different companion flange patterns Toyota has used on their 4x4s, not to mention fine versus coarse spline.
This does not even touch non-Toyota parts or many of the other variations of parts that might get broken.
In summary, while it is a noble cause to offer a Cruise Moab inventory of spare parts that might get broken, I do not believe that Cruise Moab should buy and inventory spare parts because of the many variations. I believe that it is worthwhile to list and inventory spare parts that participants bring with them. Happy cruisin'!