Welcome Sue!

The opening of The Incident was the best scene of the show, ever! Watching it for the second time I caught the thread of the bigger picture that the writers weaved all episode...heck since the start of the show.
Yes, I think it's pretty obvious that Jacob and Darkman(Bubbaman's name for the other guy) are Christ-like figure verses Satan figure. The coming war will be the ultimate battle of good and evil for the soul of mankind. The destiny versus free will concepts.
The evil in most mythology/religion has power over the dead, so yes Darkman would control in some way Locke, Alex, Yemi, and others. According to the producers Locke is similar to the antagonist in Stephen King's The Stand and The Dark Tower series...forgot the character's name...but he has the power of necromancy.
I also think what we were told was Jacob's cabin is the cabin Rose and Bernard were living in, but the ash isn't their bodies...it was always there in other shows when we've seen the cabin. Yeah, in Locke's dream we were told Horace built the cabin...but the dream was incoherent and dreams by their very nature aren't linear. We often confuse things in dreams...and I think that's what happened here. Or it could be Horace started the cabin and Rose and Bernard moved in and finished it. I don't think we saw R/B's cabin then the one known as Jacob's back-to-back by coincidence. I think the presence in the cabin was always Darkman...Jacob probably never lived there. After all it was Ben who said so...Ben lies and he admitted to never having seen or spoken to Jacob. Richard went right to the statue not the cabin when he took the group to Jacob...the statue was where Jacob lived in the 1800's, too.
The Losties probably caused the incident...just like Miles told them and us.