Well, if the 1st player 100 unit doesn't have both a carry isolation switch and an EOS switch, that sounds to me like it's missing something. If you have the schematic you can check on this - AFAIK there is no reason for the 1st player 100 unit to be different from the others in this regard.
The long machine screws, switches, and spacers are the same ones used on virtually any AG type relay, so if you have a salvage relay you can just steal the parts from there. The plastic piece is not an actuator, it is just a bumper placed between the back of the EOS switch blade and the stepper unit metal bracket. The nuts are the difficult item to find, I usually steal them from salvage score units when I need them. If you really get in a pinch, you can use #4-40 machine screws and nuts if you are willing to drill out the pathway for the screws a little bit.
Steve Young may indeed have these parts, so it's worth checking with him. In the parts catalogs I have, the individual parts are not called out, but the complete assembly is. The switch assembly you are looking for is B-15906.
switch_assembly_(resized).jpg
- TimMe