I just wanted to mention that you would not see two years into the past.
First of all, if you teleport a mirror 1 light year away, and actually want to see the earth, you would have to put it against the sun's light, so all you would see is the shadowed side of the Earth.
So we'll assume that the entire Earth is lit. That means that light has been bouncing off the Earth for at least on year, unless as soon as you plopped the mirror down the Earth became illuminated.
That means that light had already been traveling in the direction of the mirror, and was already at the mirror when you dropped it. That means that the time between when the mirror was placed and when the light returns to earth is only one year.
However, if your referring to how long ago since the light originally left earth, than yes, you would be seeing two years into the past.