JP, that's what I've thought the flash sideways scenes have been for a while now, and I think we're right!
And I really hope Jacob and the MiB are not good... or bad, actually. I will be sorely disappointed if it turns out to be a battle of good versus evil. But yes, like you say, they're both manipulative and Jacob even seems moreso at times because he never explains anything, just expects his pawns to do as they say.
Interesting what you mention about Jacob not being God because he can't absolve sins. Maybe Jacob is more like an analog to Jesus though, in which case... could Jesus absolve sins? I'd think so, but maybe not. I did think that Jacob's dousing Richard in the ocean was reminiscent of baptism though.
It seems that the theory that the island is trying to keep evil contained could be true though, and is true unless Jacob is not 'good.' It's not the worst thing that the creators could do with the show, but it isn't the best. I'd still like to see that maybe Jacob isn't right in keeping the MiB there.
Also - what Jacob said about bringing people to the island to show the MiB that people are naturally good and capable of change makes sense considering what has happened on the island. I'll have to think about it more, but it seems plausible. Hopefully the creators comment on how Jacob had no right to do that, to use people in his little game with the MiB.
There definitely seems to be a Nature of Good and Evil theme dominating now. Are humans innately good or innately evil? It's an old philosophical debate, but not an uninteresting one for sure.
Let's hope they pull off something surprising and profound. And, let's hope the best characters get awesome roles in the final episodes.