What is this thing with the actors signing-off on likenesses? I was under the impression that actors signed away such marketing rights when they agreed to do Trek [or most franchises].
Contracts of the 80s and 90s (and beyond) have very different wording to those of the 60s. Recently it was mentioned here that the original cover of the forthcoming Kevin Ryan "Errand of Fury" novel was to have featured the TOS Organians, but that there was no permission for one of the deceased actors so the cover would be changing.
DC Comics had to draw a bald Garth of Izar, a ST III Captain Styles with no mustache, and a fat guy who vaguely-resembled Harry Mudd's physique for various issues. Due to likeness permissions not being on record. When DC wanted to bring back Saavik in Series II, she had to resemble Robin Curtis, not Kirstie Alley, even though Kirstie's Saavik was more popular. And so on.
Sometimes the families of deceased ST guests might be happy to sign off. Others might insist on a royalty. Others might want approval of finished sketches, or they might refuse outright. It may vary from actor to actor, too, depending on their (and their agents') clout when contracts were signed. Welcome to Hollywood: a land of red tape.
