Indeed, Cynthia Watros is in this movie as Elizabeth talking to Desmond. Though I'm just wondering how she ended up as a 'rehab patient'(?) where Hurley is also in there trying to reduce his weight (as seen from the previous episodes).
Anyway, this last episode is really suspended. The ending is not so understandable. I think the writer did expect the audience that there is a season 3 coming.
I just hope the next season will give light to more unclear/hanging events that were happened.
Just can't wait further for season 3.