You finished the game already? Well, you kind of have to pay attention to the voxophones, or you're gonna miss it Most of the Luteces' voxophones are near the game's ending. They begin mostly in Emporia, I think, but there are a few before that (I remember there's one in Soldier's Field.) Take a look at Bioshock's wiki, or maybe IGN, there's probably a voxophone guide in them
But yeah, Robert is Rosalind's male counterpart. That's why they look so much alike. Robert comes from Booker's reality, Rosalind from Comstock's. They were both working in the same contraption, and because of that they could comunicate through the walls. Then Robert stepped over to Rosalind's reality in Columbia
I didn't really get what the nose-bleed meant, other then that it happened when your brain was affected by the memories of one of your other selves in the same timeline. I guess it's your brain overloading or something?
Not to sound naughty, but I was kinda surprised that the Luteces had only one bed in the house.. <X O ... did.. they sleep.. in the same bed? w-what would that mean?