Another "Christmas list" hint
I wonder if when we get to the Christmas special the doctor will say
"I didn't not ask for a companion on my Christmas list!"
I have only skimmed through this thread, so I don't know if this has been covered yet.,
but is it possible that the gun-shot hole in the Stetson might be a reference to the Impossible Astronaut, in which River Song shoots through his stetson with a gun. Could it be the same hat?
The Doctor got his Stetson in "Closing Time" from Craig