There's one thing I would add to the list of supplies: a portable toilet. If this has to be a shelter for several days, well...... I wonder if a small chemical toilet would give off harmful fumes in a sealed up room.
The best solution I know is two 5 gal buckets of sand, three empty buckets and a box of small plastic garbage pail bags.
Use an empty bucket that has been lined with a plastic garbage pail bag to urinate and defecate into. Cover your waste with sand and seal the bag. Repeat each time necessary.