First of all, I thought the trailer was awesome! However, there are two things I would like to speculate on ahead of Thursday:
Are we going back to the Sea of the Damned to rescue Merrick? I would love to be able to revisit Dead Man's Grotto or another island within the underworld. Secondly, I am assuming Wanda and Duke are working with the Dark Brethren.
My guess is that the "information" Wanda and Duke need involves freeing Davy Jones from his prison. I'm not sure why they would go after Merrick and not Belle, but maybe Merrick has knowledge on where the Ferryman is keeping Davy?
It feels like Rare is building up to something big. Rathbone is still out there somewhere and we still don't know the identity of the "Captain." (my guesses are that the "Captain" is either an original character or someone like LeChuck. I know people have been guessing Captain Hook, but to be honest, I don't think the guy who is regularly running away from crocodiles could effectively lead a team of piratical bad guys like the Dark Brethren.)