Honestly, I wouldn't put a backsplash on with the 6" granite backsplash.

I agree with cpartist. I've always heard that it's one or the other, but not both.

I think the only way to make a backsplash work there is if the tile backsplash was the same color as the wall. But that seems kind of pointless.

No to the double backsplash. You could try removing the short granite splash, but you don't know how well the countertop is scribed to the wall (the granite splash allows the fabricator some leeway).