[SPOILERS] Glitches, detail overlooks, or maybe important hints?

I've just finished my 2nd playthrough, this time on 1999 Mode, getting all achievements possible. I'm sad that this is the end for now and I can't wait for the DLCs to come! But that is not the case... I've spotted a few interesting things in the ending section of the game I'd like to share.

The thing is, my Anna/Elizabeth was wearing a bird pendant through whole game. But, in the ending, during the second boat scene, she wore a cage pendant! This happens only in the second one... Is this a glitch or a design overlook? Or maybe she's another version of Elizabeth? I'd be thankful if somebody could check whether the pendant change in the boat scenes if the cage pendant is chosen?

To make things more interesting, I'd like to notice that the Elizabeth that drowns you has no pendant at all! I can't figure out what does Booker mean when he says "who are you"... Does he mean that she's not "his" Elizabeth, or is he surprised by appearance of other versions of her?

Another thing I've spotted is the fact that the doors in Booker's room change. Most of the time, the doors have knob on the right side, but in the scene where you give baby Anna to Letuce, the doors gave knob on the left side. Another overlook, or maybe an indicator whether it was happening in reality? In that case, that would mean that after-credits scene is a hallucination/imagined.

What are your thoughts about that?