[quote=Zelda Wiki]Like the land of Hyrule, Labrynna is a country blessed with a long, rich history. It is unknown how the land of Labrynna was formed, though it is assumed by many to have been created, like the land of Termina, as a side effect of the Golden Goddesses' creation of the land of Hyrule.[/quote]

That excerpt from Zelda Wiki seems to indicate otherwise, that they are indeed parallel worlds like Termina is.

Edit: Zelda Wiki could of course be wrong. If it is, then this is what happens when a story-driven franchise is forced to follow the stupid "no story allowed" policies of Shigeru Miyamoto. xD

In any case, there are no indications or even hints of any Sheikah people from Labrynna. Impa is the only Sheikah in the Oracle games and she was sent to those kingdoms from Hyrule to retrieve the Oracles themselves. So I'd still have to say no the Sheikah idea.