Why not use 20' & 40' SHIPPING CONTAINERS (try overlook the Cabal stigma), because they are totally weatherproof, secure & rodent proof & commonly are built into multi-story homes, even. Frame a front door and window in the front container opening, stake the steel container doors open, top those off with a sloped roof and that gives you an open, covered porch for using a propane BBQ or generator. Insulate, ventilate, add a small wood or pellet stove, a power source, composting toilet & interior water tank, sink, some basic electric and you have TOTALLY safe, secure and weatherproof shelter. Easily transported to the disaster site by roll-off truck w/ forklift. REUSEABLE. Won't blow over, set on railroad ties.
Cut down some pallet racks & turn them into adjustable bunk beds. Later cut in some windows, saving the metal cutouts as storm shutters - hinge those topside and brace open, close in bad weather.
Tell the building inspectors to go to hell - it's pre-engineered.