[quote=@Double]
You know those are all parallel worlds, right? As such, I can't allow such a character, no.
[/quote]

Actually Labrynna and Holodrum are confirmed to exist in the same world as Hyrule, because in both games characters can physically travel from one place to another. Zelda and Impa travel there from Hyrule, which means that the three kingdoms are all in the same universe. Link is only transported there via the Triforce as a means to start the stories of each game.

Not trying to overrule GM, just saying. But I don't think the Shiekah tribes have any branches outside of Hyrule, so Labrynna probably wouldn't have any serving its royal family. And such a character wouldn't be able to "check on places like Termina", because that IS confirmed to be a parallel world.