Do you know if there's any way to go back to the place in act 2 when you have to talk to those four different people for the different missions? It appears as if I went up to the same guy twice & so the game has taken me back to do 1 of the missions I already completed. Do you know if there's anyway I can bypass this since I've already completed it & go back to select another mission that I haven't completed yet?

It seems everyone is having this problem. But if you already went into it, you MUST beat the mission. The longest of the 4 missions only took me 20 minutes to complete, it's not that difficult. To prevent it from happening in the future, save your game in a different save file. So incase you re-enter a mission again, you can simply load the other save file.