Nice setup. Sounds to me like good half-doors would be better for you with children if they're still so young they can't resist trying to open doors. Not sure if anyone ever made half doors with child-locks like many standard car doors have.Does anyone know who makes some child friendly half doors or tube doors? Something that will actually lock with a key so they don't open the door when the vehicle is in motion?
Another option for you that I'm guessing you thought of - keep one of your real doors on the vehicle next to where the young child sits? So it will look a little odd, but the rest of the fam get to have full doors-off feeling and the young'un stays safe.