I would also be concerned about restricting the animal fat and proteins in small children's diets.
There's just too much peer reviewed scientific evidence supporting the need for those micronutrients found in meat and dairy for proper brain development. Your brain is after all... mostly fat and water. And young children especially need a lot of those B vitamins, some only found in meat sources, to maintain healthy myelin production. Without them you can get a range of disorders spanning depression, anxiety, and cognitive/behavioral developmental delays.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3137939/