If you're going to have kids at your wedding reception, don't forget to ask your caterer about a reduced price option for some kid-friendly foods. You may want to ask the parents what type of food their kids eat. Chicken fingers and spaghetti are popular items for kids, but better to know in advance if the kids don't eat meat or can't eat pasta.
I've said before that you don't need to worry about your guests' food allergies but when it comes to kids you should find out if there is something they won't or can't eat. You don't want parents running to a local market or diner to get food for their kids. And unlike a bar mitzvah where half the guest list is under 15, you are probably only dealing with a limited number of children so reaching out to parents shouldn't be too difficult. Especially over email.