Since The Wicked Witch is back (and from the promo, "more powerful than ever"), I'm betting that she's going to bring the pain down on Gold, giving him a chance at redemption (just like Regina and Snarming) after much penance.
Since The Author was trapped before writing Emma's full story and August (who is a writer, remember) has returned, I'm guessing she's both not bound entirely by the book and has the capacity to change it for everyone (with his guiding advice). Emma is obviously going to find Lily and turn Mal, leaving whatever crazy DeVil and WW have yet to impose upon the residents.
As for Snarming, I'm sure they're going to continue to be up to no good...retrospectively, nearly all of their decisions were self centered. From Snow spilling the beans to Cora and Charming remaining the doppelganger, to this current batch of BS, I'd say the threat of turning isn't going to be from Emma but rather their overzealous fanaticism that doesn't fit in the world they now occupy. Truly, in the 21st century...everyone is a little good and a little bad at the same time.
I definitely agree about the casting. I was excited for Tamra Tunie and Tom Sizemore, and I wasn't disappointed. I couldn't help but think of thematic threads this show shares with Twilight (wolfishly starving first nations vs old money settlers with blood on their hands); this is a nightmare juxtaposed in a quaint town surrounded by verdant fog that keeps them insulated from intrusions by the real world.