Ehhhh... I've seen the Lal suggestion a few times, and while it's quite possible she's an android I don't buy that it's Lal herself. Lal barely worked enough to function- and then only for a few days. This girl is talking normally (something that Data struggled with, though I admit Lore had no such problem), clearly has some serious physical capabilities that we haven't seen from any previous android (though can you imagine Brent Spiner doing flip-kicks like that?), etc.- if she's an android, she's leaps and bounds ahead of any of Soong's work- so how is that possible? Who could have taken Soong's android work and made it into something like this? (Safe to say if it was the Romulans, they'd have completed her with pointy ears, right? Why make her look human?)
I'm guessing she's not an android. I'm guessing she's Borg- but without obvious implants, perhaps for spying purposes. That would both explain the appearances of Hugh, the weird Borg cube we saw, and possibly explain why Picard got in touch with the only friendly Borg in Federation space. If the Tal Shiar (what's left of it) or other organizations found out about such a being, they might very well decide exterminating her is the best bet- thus the danger she's in.
The reality of it is though, I'm just looking forward to seeing what they come up with- my own personal ideas and theories are simply guesses, and I'm honestly looking forward to being proven wrong.