No matter what you do, you will have success. A local family did a similar project for kids in Haiti giving them regular film cameras to work with and black and white film, teaching them darkroom work as well.
Know that doesn't match your plan as you described. But the thought occurred to me. You might give the kids real cameras (that could be donated to you) that they can load with film (could be expired). The kids might get to keep the cameras if they want. Then they might have a chance to continue if it sparks a passion.