1) Possible but it's not like the Doctor has travelled alone before. But some were a bit grumpier, I'll admit.
2) As much as it bothered me... you can't blame her. He never talks of it, wears no ring, nothing.
3) I was thinking the same thing. Alons the lines of "Hey, we killed Rory again and again and the fans loved him! Let's kill her again and again and the fans will love her. Hahaha!"