Can any 68Cs share a JST? 68C to RN?

You won't receieve anything that will eliminate a prerequisite of nursing school (such as chemistry, anatomy and physiology, speech, statistics, etc), though you may end up with some elective credits that you can apply towards a 4-year degree.
I completed my BSN about 5 years ago. My advice would be to CLEP as many of the prerequisites as possible (you can CLEP almost everything), and then complete any remaining courses necessary for entry into an RN program at a community college. Next, enroll in an accelerated RN program that will allow you to graduate in 14-16 months. That is your quickest path (and the path I would take if I were in your shoes).

You actually don't get any constive credit. You have to check with your specific school. Clep what ever you can and what you can't take them once you are actually enrolled in the core nursing courses look into AECP. My 68C class had 4 people get commissioned as BSN's that way.

Jst is only a suggestion of possible credits for a school to accept. They're not actual credits. Most accredited nursing schools will not accept jst recommendations or acceptance into an RN program.
If you are looking 4 the credits that you will be recommended once you complete 68c, you can find BMO West listed on the ace website, American Council for education. But, as I said, jst are not credits, they are only recommendations. You have to find a college that is willing to accept the recommendations and give you credit for them.