Thanks for your appreciation. I think the primary reason we have multiple channels of communication is to help in switching between the channels depending on accessibility in the country being piloted. SMS, radio and street plays are accessible and viable options in almost all countries.
Children can be reached out to by creating simple visual cues of the question and the options for the same questions asked to the parents, making it easier for children to comprehend. Example would be showing the children options as a picture of one, two and three bottles of milk and asking them to pick based on their intake. If suppose the required intake is two and the child picks one bottle, it displays maybe something like 'Ask mummy for one more bottle'.
This is a very basic example I could think of in a moment. I'm sure we can polish it to include the children in the program seamlessly.