This character was Chekov's yellow skinned Drill Thrall in Gamesters of Triskellion, played by actress Jane Ross, also known as Jane Breslaw. There is very little information that I have seen on the character. Has anyone ever seen any speculation or definitive information on this character or her race of origin? CCC.
When it comes to definitive information, I think that all that exists regarding this character are the few minutes of screen time devoted to her in "Gamesters of Triskelion" and whatever scant information might be in the actual shooting script for that episode that didn't make it into the final cut. (I've looked: there's nothing really of value in non-dialogue script direction regarding the character.) When it comes to unofficial speculative information about this character, I haven't seen any. She's a relatively minor character existing in only one episode and, aside from being from an otherwise unportrayed humanoid species, she doesn't seem to have anything compelling going on with her. The good news is that this means that she's a clean slate: you can come up with whatever backstory and speculation you'd like for this character. I look forward to your fan fiction on this underexplored character.
Here is my thinking. We know Orion is not a member world from Journey to Babel, and I believe your world has to be a member, or you are at least a Fed citizen, to be in Starfleet, yet in the JJverse we have an Orion in Starfleet. There are all kinds of possible explanations for that. In GoT we see an Andorian Thrall. Me personally, I like to custom as many different looking aliens as Starfleet crew action figures as I can, just looks better in the group pics, so, I wanted to see if there was any info that made it reasonable to assume her race was a member world. CCC.
Why can't the Orions in Starfleet be Federation citizens? Worf was a UFP citizen. Though even that isn't required as Ro was a member of Starfleet while her homeworld Bajor wasn't a member of the UFP. The inference here is the various races seen are from disparate areas of space.
The way I saw it, joining Starfleet was a path to citizenship, much like how if you join the US Armed Forces and serve for however many years, you're awarded with citizenship.
It is reasonable to assume that human men have married orion women and had children, who would be Federation citizens, as would be the wife. It is also possible to assume that the chain of events in the JJverse changed the point of view of the Orion government, causing them to join. We don't know, but there she is. We don't know if Marta (Whom Gods Destroy) was a citizen, but you don't have to be a citizen to be locked up for being criminally insane. The Orion were not members in ToS, but were they in TMP? Did the Troyans join? Did the Cheronites manage to keep from destroying themselves this time? and join? The Gorn? It almost looked like the guy in the EV suit when Epsilon IX was destroyed was a Gorn. Enquiring minds want to know. CCC.
I assumed Tamoon was from a faraway world unknown to the Federation, primarily because her skin and hair colors were unlike any other species we knew about. Of course, that's not proof, it's just an impression.
It's also reasonable to assume that any Orion can become a naturalized UFP citizen and any Orion born in UFP territory is a UFP citizen. No one knows the answers to those questions. They've never been addressed on screen.
They didn't actually say that Orion isn't part of the Federation, only that they would profit from Corridan not joining and being protected under Federation law. The Tellerites are certainly supposed to be part of the Federation and some of them were in on the take. The important thing is not to assume these "monolithic" cultures. Just because there are a lot of Orions that are pirates by trade doesn't mean the whole planet is a den of theives that all steal constantly. Same thing about the Tellerites that were implicated by Sarek in that same episode, it doesn't mean that they were all involved, or it could have been sanctioned by the planetary government even though it was in violation of the Federation Charter. I'd go with pale Orion. That sounds good to me, why does everybody have to be the same exact color. It's not as if we haven't seen a species that has more than one color in existence, right?
I disagree with her being Orion. If she was, Chekov would not have been so nervous with her because he would have known she was. Orion females were well known to Pike (The Cage/The Menagerie), so would still be well known by Kirk's time. As for TAS, the yellow men/green women idea was contradicted in Enterprise, where the men were green too. They could be a sub group of Orion, like we saw with the Andorians in Enterprise, but would they not have the pheromone ability? CCC.