Road Blasters is definately optical, so there are no pots. The grips, triggers, and thumb buttons match on SOME of them, but some of them come with a different grip assembly. If you look at a picture, you can see the different grips right off, they're blue with red thumb buttons. I think the blue grips would probably attach to a SW yoke if you move them over complete, but the thumb buttons and triggers are definately not interchangeable, don't know about the internal switches.
The springs on the X axis should be interchangeable, and I think the large X axis gear is, too. The Y axis housing is shaped differently, so the bodies will not swap, either- but the X axis frame might.
As for your beat up yoke, there was a guy selling repro thumb buttons as of a month ago. Springs seem to be in short supply, but you can always have a go at making your own. Pots can be bought from Happ, but are like $20 each. Triggers will have to come from another yoke somewhere, so expect those to be tough to get. Ditto for the gears- they tend to be broken, and replacements will either come off of another dead yoke, or you'll be searching for suitable replacement gears on the net- I've seen some links posted, but never any confirmation if they panned out or not.