I found another inspiring documentary that gives me ideas for further research and experiment:
As for the interior, I could use my previous experiment in above for the furniture and energy source at daytime. They wont be able to use a chair since the height is not high enough for them to sit on a chair, therefor crates could be use for tables and storages inside the shelter. For the energy source at daytime they could use the solar plastic bottle and for nighttime they could use some candles. For the water supplies, they could store it in the bottles, and use it to wash their clothes, dishes and other things.