What we DO know about the Shiekah is that they had connections with the Oocca race, so if the entire Shiekah race is to appear in SS, we may see the Oocca as well. But something else I noticed was that the video shows Link running towards her, like he's trying to talk to her. This new girl reminds me a LOT of Shiek, even so far as to suggest a similar role of a mysterious ally. I highly doubt she has affiliations with Ghirahim, if only because the Shiekah were a noble people. We do also know that the Shiekah became servants for the Royal Family and were loyal to the Goddesses. That bright glowy heavenly light behind the girl could potentially reinforce this, idk, this is mostly speculation. But I'm thinking that if she is a Shiekah and if all we know about the Shiekah's noble qualities hold true in the time period SS takes place in, this girl may have been sent by someone, her tribe, the Goddesses, who knows, to find Zelda before Ghirahim does.
Again, all speculation, but I must say, I LOVE her design.
I second this!
She looks like a mix between an Oocca and a sheikah, so who says that the Oocca and Sheikah cannot share the same ancestor?