Movie 43 is about the hardest R Rated comedy ever. So the actors were definitely stunned when they read the script. However that's what appealed to them too, because Hugh Jackman, Halle Berry and Kate Winslet had never had the opportunity to push the envelope so much.
Can someone explain to me how they got all of these legit actors/actresses in this?
Because they all got a chance to push the envelope as far as possible, and the crew worked entirely around their schedules. Actors could choose the date and location for the filming of their scene, that's why everyone signed on.