Rebuilding those speakers may be something of a project. If you are just looking for some good sounding speakers for your own recreation, they aren't worth the hassle, but if you want to restore them for sentimental reasons, it may be able to be done, but it will require time, patience, and effort on your part. In order to get them to sound like they are supposed to from replacing the woofers, you need to replace them with woofers that have similar T/S parameters. The only way to do that is to reach out to Yorkville and ask them for the T/S specs for the woofers. If the original specs aren't available, there isn't going to be a reliable way to get that speaker to sound right.
As for the crossover, the only part that might have fallen out of tolerance is the capacitors. I would replace the capacitors with ones that have the same values as the original caps. If you can't read the original values off of the existing caps, ask Yorkville what they were. If Yorkville can't tell you, and you can't see what they are from the existing crossover,.. um,.. you are screwed.