Ok, let's get some things out of the way. I like the theory that Aaron is Jacob. I might even go as far to say that David is the MIB, but I'm not set on that (It would be a little cheap I think, to introduce a character so late in the game and have him be so important). I think that since Aaron has been out of the picture since the middle of last season, he will play a big role in the series finale.
So I just rewatched "Maternity Leave" from S2 and noticed a few things. There were some interesting parallels between that episode and the goings on in the present season. I know this is already know, but it's cool to think about.
In "Maternity Leave" Rousseau tells Claire that Aaron might be infected. This freaks the crap out of Claire and she starts to remember the 2 weeks she was held captive by the others. During those two weeks we find out that Ethan was her main doctor. Ethan told Claire that once Aaron was born she would go back to her people and Aaron would stay with the others. His reason is that they didn't have enough vaccine for Aaron and Claire if Claire got infected. Then Ethan paused for a minute. What he said next has turned into a common theme throughout the show; that of free will. Ethan said he wouldn't make Claire leave Aaron behind, she had a choice. This has been seen more and more as the others seem bound to give the Losties a choice in everything. Dogen couldn't kill Sayid, someone else had to CHOOSE to do it. Ben had to choose to kill Jacob. The oceanic 6 (mostly) chose to come back to the island.
When Alex forces Claire away from the underground baby lair, she tells Claire that they were planning on cutting Aaron out of her, consequentially killing her.
It seems babies have been very important in Lost. It appears the post-dharma others knew a little something about the infection and this might be the root of their obsession with babies. Maybe infants react differently to the infection. There is obviously something going on with fertility.
So the questions are, was Aaron ever infected? Did Ethan cure him? Is Aaron the Littleton on the lists? What would have happened if the others had taken Aaron? Would he be integrated into the others, just like Alex? How does this all play into the endgame?
Like I said, I think Aaron will play a huge role in the series finale. He has been emphasized too much to be forgotten. Let me know what you all think,
Don't hate, conversate. (Wow that's corny.)