Russ, does the term "blind leading the blind" ring a bell? I was tempted to respond via e-mail, but thought it might be better to give others a chance to add/subtract to my response to your questions.
1. There are at least 3-4 combinations of transmission outputs/computer requirements/speedo needs that you are dealing with. The JTR available book on TPI swapping does address the solutions in part for your specific combinations. It does advise, wisely, not to eliminate the VSS to your computer as it is needed for proper coast down etc. You can bypass with mixed results.
2. The major catalog speed merchants have pictures/dimensions on the electric speedos. I plan to swap both the tach (mine works..darn) and speedo to matching set..probably Autometer. This takes out the extra cost/complexity of having both mechanical and electronic outputs. Elsewhere in this list is info on that, fitting is no brainer I guess.
3. I have since learned the small 305 wheel works on the one piece seal engines ok. I plan to use the small clutch (10.5") and again plan to task my wee tires to be weak link. As for price, as little as possible for a good one is my immediate read on that question.
4. Got me here...IF it needs to be moved and you used the JTR style crossmember...maybe you will need a drill bit (you already have the rest) to move it a bit. Somebody here has that answer I am sure.
5. Price to expect for your transmission?...similar to reverse of above...as much as possible. Ebay is a possibility. I would sell it locally (no shipping) with no reserve price and hope for the best.
Hope this helps open up further discussion/reference for us both john