Well, it was always part of the movie's original script, too - the scenes with this dialogue were even filmed IIRC. Several novels subsequently tackled this story twist, including the novelizations and the separate novel The Pandora Principle.
At least one scene with the Romulan info has been viewed by more than a few people and there is even a copy of it on Youtube last I knew.
Personally, I don't like the idea that the person in STIII was Janice Rand, as the career development of the character would almost make sense if we ignored that cameo.
Also, it doesn't make much sense to think that this person had been aboard the Enterprise in STII and then boarded the Firenze for a ride home. The sorry state of the ship wouldn't come as such a shock to her, then. Sure, there was some extra damage there vs. what we saw in STII - but the scene tries to show her shocked over very fact that the ship is damaged in the first place.
While I don't mind Rand being the one in Spacedock, (Her wry expression as she shakes her head works best if she is Rand) I do have to agree that her reaction would seem strange had she witnessed the events of STII.
"Flashback" inexplicably promotes her by three steps vs. what was shown in ST6:TUC. If we say that this promotion was all in Tuvok's feverish mind, then Rand's promotions are pretty logical: from noncom yeoman to noncom transporter specialist to noncom SF HQ specialist, she'd gather experience and brownie points, and eventually jump to "mustang", i.e. get her officer commission to Ensign and then a quick promotion to Lt (jg) as shown in ST:TUC, without Academy attendance. Now that would show her annoying big sister who always had to brag about being a full Commander!
I prefer to think of most of "Flashback" as being in Tuvok's feverish mind! Especially the implied death of Valtane.
I also thought perhaps the cadet jumpsuit was interchangeable with the monster maroon jacket for officers
Could well be. The original ideas on the use of those uniforms have been contradicted by later movies and episodes, and it's entirely possible that the jumpsuit could be decorated with the proper colors and pins and whatnot to denote that an officer is wearing it.
Timo Saloniemi
Other than promotional images and the like, did we ever get a good look at Rand's rank pins during her extremely short cameo(s) in ST:IV? Without on screen confirmation, I'd be happy to accept her as a hard working jumpsuit officer. I would rather retcon that appearance than her ST:III cameo.
Unless I was just going to be a command barking figure head, I personally would prefer the idea of getting to wear more casual attire when I am performing duties (officer or not) that demanded I not soil my uniform. That way I can be all prim and proper when the Klingons come to visit.