the point of the alt timeline
this is my first stab at a theory.
thanks to other posts i was wondering how the alt is going to have influenced the 5 seasons of nonalt, because it has to, otherwise one tiny season of alt seems odd.
maybe the point of it is that jacob and mib, once the alt is created in 1977, have two the ‘sides’ [one represented by black and one by white] that seem to be important to the coming ‘war’.
one dude is from the original timeline and one is from the alt.
maybe when mib visited jacob on the beach he came through the temple from the alt.
maybe they can not kill each other because they are not from the same timeline.

I’m with you runkaterun. Click my username to read my older theories on the same idea.
I think the point of it is to help explain much of the island phenomena. The island is a special place where time lines can merge, diverge, or even exist simultaneously. The whispers and possibly other things could be explained using this. The point you brought up is also good. Perhaps Jacob and his friend are from two different time lines.
There have been theories on here basically saying that Jacob is Claire’s baby from the alt time line.
I think that the kids are going to fit in somewhere major this season – otherwise why would it matter that any of the main characters had them? I think a relevant thing about Aaron is that he is the only kid that will, without a doubt, still exist in the ALT.
Desmond and Penny might never have gotten back together or have been together at all meaning no Charlie Hume. Jin and Sun couldn’t have children so no Ji Yeon. Other characters that didn’t have kids in the main time might end up having kids in the ALT.
It’s a cool thought that maybe Jacob is Aaron from the main timeline and that MIB is an ALT kid that did not exist in the main timeline.