I'm not sure all of your questions can be answered, but I've found some very interesting information to answer some of them:
- From Ian Spelling's "Sci-Fi" syndicated column:
Interview with Rick Berman (January 22 [I assume 1996): Miles O'Brien was going to be involved
- December 30 in TV Guide: It would be 40 minutes long and (of course) filmed in IMAX 3D with a draft supposed to be ready by early January 1997
- November 3 from Star Trek Communicator:
What is happening on the IMAX movie?
BERMAN: We've completed a story that was written by myself and Hans Tobeason.
I'm very pleased with it and Paramount is very pleased as well. It has
now gone off to IMAX. We're just waiting to see what the next step is
going to be.
This indicates to me that there is a script out there somewhere!
Are you planning on featuring more than one Star Trek crew in this
IMAX film?
BERMAN: At the moment, it features one well-known Star Trek character [probably O'Brien] and a
number of other actors who are not known. There is a good chance that
there will be some peripheral performances by other known Star Trek
characters.
- June 11 1997 Star Trek Communicator: it was intended to have some scientific/educational elements to it, but still predominately entertainment
- February 25 1997 Star Trek Communicator: it had a budget of $10 million
Based on the above information, it seems most likely that we were going to see a new ship and crew (with O'Brien aboard it). The details other than this though seem to be awfully scant!