Honestly, go with what your family will eat. With a toddler, y'all aren't going to be hiking out any great distances because one of you will be carrying the kid as well as your own pack. Dehydrated is good if you have water available. If you have to go by foot, then you are going to need some sort of cart to haul the little one and that can also be used to haul your supplies. MREs can be doable, but you really have to make sure you are eating prunes or some other natural laxative with them, they will stop you up with the preservatives in them.
If you know where you are bugging out to, then make arrangements to have supplies there with family, friends, or in a storage locker nearby. If you are definitely bugging out to a remote location, try to have supplies buried along the route and a map to find them.
Some things you might look at as far as road food, would be crackers with cheese or peanut butter, foil packets of tuna, ramen, those Compleats meals that are shelf stable, pop top meals (ravioli, spaghetti-o's, mac and cheese). If you are going by car and you have a cooler, you can always use foil and heat things like hot dog on the motor.
I would be certain to pin identification and contact numbers inside the toddler's clothing in case you get separated. If nothing else, write his name, birthdate, SS, your name, and numbers on his back or belly with a Sharpie. It will eventually rub off, but he can't lose them if the worst happens.
