Hi, Kathleen!
I am so happy to hear you are planning lunch at Be Our Guest! This is the most beautiful restaurant, and going for lunch is great way to see it without having to get a dinner reservation.
Seating is from 11am - 2pm. Guests will line up by 10:30am. I suggest getting in line with the rest of the crowd early as they get everyone in and seated fairly quickly.
My family's plan is always to skip breakfast, get into the Magic Kingdom at rope drop and enjoy several attractions while the park is relatively empty. Then, we have an early lunch at Be Our Guest. By noon, we have really squeezed in lots of that Disney magic! Since you are going in August, this is a great way to beat the heat. Get an early start then head back to your resort for a relaxing afternoon at the pool.
Wishing you a wonderful vacation!
Let me know if you have any other planning questions; We are happy to help!