You don't mention what type of flooring you have to clean up the mess from. Try using a pet enzyme cleaner, like Petzyme (there are others found at a pet store), that breaks down the residue and cuts through the smells, plus is safe for animals and carpets and floors. You can try baking soda water or white vinegar, which are safe. You might want to put a litter box down in the basement for the cats and keep it clean in the future. Be very careful with pesticides as this can kill animals. If you keep the area clean, there shouldn't be a lot of bugs to deal with.