I strongly feel ageplay should not involve actual children. But, these are fetish drawings so the children are not real, just there for illustrating the feelings of being exposed and humiliated.
I like some of the aspects of the diaper fetish. However, I would not be changing soiled diapers on an adult. It would be far more fun to make him wear them and remind him he is wearing a diaper in subtle and less than subtle ways. Some other elements interest me as well.