Vonda McIntyre's novelization differed from the on-screen versions in some very significant ways. There was a sub-plot that Saavik was tutoring Peter Preston in some subject and they were friends, so that's why she reacted as she did to his death, and later on she sat vigil over his body in the morgue (a custom on Hellguard to keep animals and thieves from disturbing the dead).
I would need to dig out the novels to see if there's a mention of the earring. Unfortunately, most of my Star Trek books are buried in large boxes and I can't get to most of them.
Oh, and about scripts... in my time when I worked in musical theatre, there are different kinds of scripts. I didn't get the ones including the songs (other than the bare lyrics) and the cast probably didn't get the ones with the lists of props and set pieces.
I always insisted on getting a script that included the basic dialogue and stage instructions, as I not only needed to know what stuff was needed, but who was going to use it, where, and how. Sometimes that made a hell of a difference in how it was made or what we bought.
The TWoK novel was one of my favorites because of the extra stuff on Saavik, Peter, Carol, David, and the Regulus I station. When they did the graphic novel I was very disappointed it was based on the movie and not the novel.
I think the STIII also has some inner dialogue for Saavik too, as she has some serious anger management issues. It's a real shame TWoK didn't add a brief scene to establish that Saavik was tutoring Peter in maths and a scene where she goes into a room on her own to let her anger out.