You'll be fine. It's when you close in the walls preventing air movement is why you need a vapor barrier. I've done this method tons of times and never an issue. If it's going to be a shop why bother finishing the floor. Unless you want to spend the money and epoxy it for looks.

You can use PT for the sill plate if you want but it's going way overboard. The sill gaskets breaks the capillary movement of moisture. You shouldn't use PT lumber inside but it's not the end of the world.