If your heart isn't set on a Class C, what about a pick-up and a 5th wheel? Lots of room and car seats would be easily accommodated in the truck. In a Class C you'd probably need a unit that has two seatbelts on the dinette seat and chair that could face forward. My concern on that would be snugging the car seat tight enough in the chair for it to be safe. I'm sure others will have better suggestions-our Endura did not have seat belts in the dinette.
What they don't know, ,,, just keep the kids safe and drive carefully.
What WHO doesn't know? If you are suggesting driving without seatbelting kids in properly, you are crazy. It's never my driving I worry about-it's other idiots on the road. No matter how safe YOU may drive you can't control the other drivers, weather conditions, or unexpected events.