So there's one thing i'm having trouble with: the killing of ALL Comstocks.
This diagram
and answer #1 of
this link explain it really well.
Branch 0 is Booker who goes through with the Baptism and becomes Comstock who goes on to make differing decisions resulting in more realities.
Branch 1 is the Booker who doesn't go through with the Baltism and goes on to make differeing decisions.
But there's one issue i have with it....
In life there is constants and variables. Constants are fewer and further between but the fact that Comstock was born at the time of Baptism and killing Comstock just after that kills all Comstocks from that moment on doesn't sit entirely right with me.
Booker before this baptism will have made hundreds of choices that splintered off into tons of other timelines. Some where he didn't join the army or died during the battle of Wounded Knee, some where he was crippled as a child or where he moved to another city ect...
So if at some point in one or many of these timelines he got baptised later on or because of a different reason and became Comstock, then the Comstocks killed by Elizabeth would've been only the ones from the other (our) Baptism at that one particular point in time and not the ones that could have occured as a result of all the different decisions Booker made throughout his life.
So picture this on that diagram above.
Branch 0 is Booker who fights at Wounded Knee, he goes on to make differing decisions spawning other realities.
Branch 1 is Booker who doesn't fight at Wounded Knee.
So one of the forks of the road from branch 0 is one that leads to the creation of Comstock. But if Booker from branch 1 goes on to commit some other sins and gets baptised and becomes Comstock then Elizabeth won't have killed any of the potential Comstocks to spawn out of that timeline as they only focused on the Booker who did participate at wounded knee, leaving a multitude of possible Comstocks alive
But I suppose since they would be different Comstocks and different Columbias or no Columbias and different Elizabeths then that's a different story and not the one being told.
I guess what i'm saying is as long as Booker existed in the first place there is possibilities for Comstocks to be born again.
Only killing Booker at his birth can truly kill all possible Comstocks.