I don’t have any confidence you’ve done the due diligence to properly handle content moderation here - it seems very haphazard and poorly thought out. It would be incredibly unethical to market this for use by children right now.
If this is an important project for you, I strongly recommend you bring on an advisor with history in child safety and education experience and make them a core part of your development. You might also consider working with a university that has a good developmental psychology program - they often do a lot of supervised research of children’s habits and could provide valuable insight.