yeah. that date is the date it always is, in the "head private eye room".
some of the timeline/2 universes thing doesn't add up 100%. Booker in game, says the baptism took place 20 years ago. And then after giving up Anna, wasted 20 years drinking, before being taken to columbia.
1875 born. Wounded knee was 1890. Anna was born 1892. 1893 anna was sold. so, when exactly did the baptism take place? before or after anna?
If before, then the timeline splits there. in one, he is reborn. Finds religion, becomes a fanatic, racist, etc, and meets Letuce. Within 3 years mind you.( a point of contention. he does appear to be about 40, when we see him and Letuce taking the child.) Using the machine, leaves him impotent. But peering into the portals of alternate timelines, he sees he needs a child. And sees an alternate version of himself who does have a child. and decides to take her. So in the end, what happens is, you go back to the baptism, every reality that has been spawned from that baptism, will not occur, if it never happens. So they drown Booker before he can be born again. The problem now is, well if booker died before being baptized, then how can that post credit scene occur?
if after, then the baptism is a reaction to both wounded knee AND giving up Anna. Its now 1893. columbia is forming, and comstock already exists. For this, we should probably consider a circular timeline. And possibly two baptisms. Simply, Booker lived through the game, but instead of drowning, choose to be reborn, and wash away his sins. in previous realties. So you have a primer situation. born in 1875. gave up anna in 1893, drank for 20 years. was taken to columbia via the twins. killed comstock. Choose to go back in time, to the baptism in 1890. now is 40ish, and has knowledge of the future. (problem. this booker would know full well what is going on. and not be delusional about prophecy, archangels, know he cant have kids, not be surprised about having to kill lady comstock, etc..) steal his own kid, and so on.
Now, in the end, booker at the nexus, would be both at the same time.
Much of the rules of alt realities get fudged here and there. if entering a new reality you "merge" with your other self, and get their memories, etc. as seen by Lin, the dead police, etc. then how is there booker and comstock? how is there male and female Letuce? How is there a revolutionary Booker and comstock in that other reality? that booker lived there. and when our booker travels to that reality his mind merges with revolutionary booker. that kindof directly flys in the face of booker=comstock.
I hope the DLC is just vignette after vignette of Booker dying, and the lutece's twins reseting him, and changing minor variables.
vigors probably should have gotten a bit more discussion admittedly. All this to do about Liz's tears... meanwhile they are just GIVING away, tonics that let you mind control people, making them murder their friends, and then inducing them to commit suicide.. it is a weird disconnect there. especially as no one else is using them. Save slate and shock jockey. If everyone did use them, ok. no explanation really needed. Or if they were, pulled back, and presented as something not available to anyone else. Aka, the shield the twins give you. ok.