In this first one it's probably just an accident that she found the camera.
In this second video you can see that the camera is behind her. But she does turn her head, so it's possible she just happened to spot it out of the corner of her eye.
But in this last one she's too quick for it to be anything but intentional. Now I won't quite go so far as to say that she's figured out how a mirror works or that she understands that Rillian = Lillian. But she's definitely learned how to find the camera when she sees it in the mirror.
And that's why you'll probably never get to see Lillian talking to Rillian.
 This could also be a play on the way left (Lillian) and right (Rillian) get reversed in a mirror.
 This happens when babies are 9 to 24 months of age. See http://tlc.howstuffworks.com/family/understanding-how-children-mature-ga6.htm. I've tested her to see if she'll reach for other things she wants (she does) or if she reaches for the camera when I hold it behind her and we're not in front of a mirror (she doesn't). It's often taken as proof that a child can recognize themselves in the mirror if you put something on their head while they're asleep (so they don't know about it) and see if they retrieve it when you put them in front of the mirror. However, Lilli doesn't reach for things on her head regardless of whether she knows they're there or not, so this method is insufficient to test her.