Burial at Sea's synopsis has been released; as well as the first five minutes of the DLC. In this DLC, you are playing as Booker Dewitt and Elizabeth, Elizabeth approaches Booker about finding a lost child named Sally. This is Booker's child, in this DLC, and Elizabeth knows that she was taken from Booker. He was gambling and she disappeared, the police telling Booker that her body was found floating in the docks. Elizabeth has sources that say she is still alive/ knows info about her, blah blah blah you get it. So anyway, now to the comparisons to her character to a character named Sally in Infinite.
In Infinite, Sally is mentioned in this voxophone and the man says "Sally! The bastard snuck in while the Vox was shootin' up the place and took my girl!". You go to the hidden button in the Salty Oyster bar and it opens a secret area where there is a picture of a woman, named Sally. There is also one in Ted's locker in Monument Island.(See image)
After seeing the photo, Booker says "I think I knew her..." How the voxophone says that a woman named Sally has been taken, and then a little girl Sally in Burial at Sea relates greatly.
Also, that "Myth or Truth" clip that Irrational Games has released as a trailer for the game has a woman that apparently been to Rapture, and when given a photo of Booker and Elizabeth she throws it on the ground, slams the door and hides from the interviewers. The year that this "show" takes place is in the '80s and this woman looks maybe 20-30, and since this game takes place in 1959, perhaps this may be Sally?