Theres lots of evidence that vegan diets without supplements can, and have, led to fatal illnesses and deficiencies in vegan children.
Children who follow unsupplemented vegan diets, are often deficient in vitamin D, calcium, iron and B12. Rickets, low bone mineral content, osteoporosis, kwashiorkor and developmental delay at higher than average incidences have been documented by researchers, including Dagnelie and van steveren (if you want to check).
More worrying is that 30% of kids in their study, weaned onto macrobiotic diets, had muscle and skin wasting.
This would suggest to me that Veganism (and a macrobiotic regime) is not an ideal diet for children to follow.
I certainly don’t think the OP is displaying the intelligence necessary for providing a sufficiently balanced and energy dense vegan diet for a toddler.