User blog comment:Pawn of Atlas/Important Discussion for Rapture Storyline page/@comment-1500935-20140403184252/@comment-867628-20140404212723

Technically, Burial at Sea is not the only mentioning of Tenenbaum's disappearance; I know many people love to reject Bioshock: Rapture as non-canonical, but it does go into deeper explanation of Tenenbaum's vanishing with the Little Sisters in a rather believable way. The Audio Diaries in Bioshock also support this explanation, detailing how Tenenbaum began to (as Fontaine put it) "grow a conscience" and cared about what happened to the Sisters.

As for Elizabeth and Booker visiting Rapture in 1960 first, then Elizabeth returning to Rapture for Burial at Sea, considering what we learned at the end of Infinite, this is hardly surprising. It's actually impossible to think about without getting a major headache; for example, did Elizabeth visit the same Rapture both times? If so, was the Rapture visited at the end of Infinite affected at all by the events in Burial at Sea? Elizabeth visiting Rapture at the end of Infinite is certainly mentioned by "Imaginary Booker" during Episode 2.