Doing that approach with randoms or friends that are new will give you a headache.
With Silent and Sneaky you just need to have a crew that is experienced with the heist and that specific approach. The Aggressive and Big Con approaches are a cake walk and all depends on what heist prep work you prefer. It's such an easy heist to do, so aside from Silent and Sneaky, you shouldn't really be dying anyways, which means hard mode is always preferred for the extra cash. You died while trying to escape the police? You go back to the exit you left with the exact amount of money you had when you left the Casino. You died before you were able to leave the Casino? You go back to the vault entrance with the exact money you looted. You died before you get to the vault? You're back at the entrance. If you or a crew member dies, you go right back to the recent check point. That doesn't even happen if someone leaves or is kicked from the heist.
You only restart the prep work when the heist has been completed. No? Who gave you that information about the Casino Heist?
