I would DEFINITELY make sure I serve morning snack. The challenge with parents giving the kids breakfast is that so often it's a rush, the kids are still groggy and therefore don't eat that much, and quite frankly, it's not always quality food that is served (because that sometimes takes too much time!).
I would say that instead of doing one of your structured activities, slide in some snack time. It will hold them over a little bit longer at lunch. And in the grand scheme of things it's more important to have kids that are content and don't have growling tummies!