My kids also police things for us, as do some of their friends. When you see something you don't like, just say something not harsh but that gets the point across.

With the food and drinks...have them out and available so the kids don't need to get in your fridge. If someone starts getting out of hand, my wife says, "Hey, this is not that kind of party." The kids laugh, but they also get the message.

It is a good thing that you're opening your home. It's also a good thing the kids want to come. Talk with them, joke with them, laugh with them, and they'll help you make it a good thing.