Mary, Your concerns and questions are at the core of what the potential of Ham radio from ISS for children can be. It is quite different for adults and for children.
Adults have the fore sight to accept results from long term efforts.
Children need closer incremental rewards to realize long term commitments. Your list of questions is a wonderful spring board for what the space program and amateur radio together can provide to the children of this planet. And you, as others, have noted that the key stumbling block to children attaining advancing interest in space craft communications is the irregularity of expected signals. This needs to be addressed in several ways. The signal must be of a nature easily understood by the child and at the same time able to capture their imagination.