If I show up before the show, willy family & I able to pay at the door and still be able to eat & see the show? Tickets to the show are sold out for every show today. (Sun. May 2, 2021)

You'll be able to see the show you just won't have a seat

But I would still show up the day of, sometimes they have people who don't show up for their reservation so then you score!

You don't have to purchase tickets. The reservation is to ensure you have a seat. What you pay for is $40 for a prefixed meal and bottomless mimosas.