If I understand correctly you basicly want to create several menucards with similar named categories (for lunch, dinner and brunch)? The naming itself is not the problem with the theme. It’s the id. If you insert the same categories (the same id) to the menucard pages then WordPress won’t be able to find the pages with those categories, since they’re on multiple pages. I hope that makes any sense 😉 You can solve this by renaming your categories to, for example, “Lunch Entrees” etc. That way you can visually seperate them. Just make sure they aren’t child categories. Later, if everything is in place, you can remove the “Lunch” bit if you want. It’s just meant to keep them apart visually.

So the only thing you need to do is renaming the categories and make them a parent category. No need to set up your menucard items again 🙂

Hope this helps!