Most of the time, the Doctor Who Christmas specials are self-contained. They are generally different in tone and directed at a more casual Doctor Who fan. If Doctor Who were football (the one played with hands, without the flopping), the Christmas Special is the Canadian Football League- the same game, but there are some slight variations that just make it feel different. Much of the time, The Doctor is not even the focus of the Christmas special and, instead, it focuses on someone else and them saving the day. That said, despite is being completely self-contained, there are usually homages to the previous series and little things here or there that connect to the next series. For example, Abigail’s Song comes to mind from A Christmas Carol. Of course, it didn’t clarify anything, or help us figure things out in any way, but it was a nice Easter egg for those paying attention.
So is there something like that in The Doctor, The Widow, and the Wardrobe? Maybe. Particularly the exchange where the forest “king and queen” tell The Doctor that he was always coming there, and they waited for him. In particular, they say three things:
“Your coming was foretold”
“We had faith. Your coming was foretold.”
“We waited, and you came.”
It is never explained who foretold The Doctor’s coming or why. It seems there is a religious connotation, which means it could have been The Silence, but that doesn’t really make sense in the grand scheme of things. Of course, if we know anything about religion in the universe, it’s that if one religion believes one thing, there is bound to be one that believes the opposite. Or, it could be someone who knows the intricacies of The Doctor’s travels, say River.
It would be cool if there was a connection to series 5 and, say, that the voice we hear in the TARDIS saying, “Silence will fall,” is still at work, moving The Doctor like a pawn on a chess board.
Or, it could be nothing, like it often is.