I was a bit surprised that the roof used on your constructions looks like corrugated iron. Do you think you can add a kind of vegetable roof, which may have a better isolation ? If the weight is not too important, it may also be a possibility to have "personnal garden" for small food.
I am thinking about a mechanism based on dry toilets collected every day/week and centralised in one place that produce electricity. The innovation can be to include within the toilets a battery that can be used by the families. These battery can then be used for day to day usage.