I do agree with the above poster that it won't be a gimme with the 50/50 and the DD. On the website, it keeps saying that the game will "morph" into something we have never seen. Unless that just means changing the music and the lifelines, I think it is definitely possibly there are 6 choices, and the 50/50/DD leave you with 3.
Can't be. The official rules on the abc.com website specifically say that for each of the questions, one of the four answers is correct.