I'll remind those unlucky folks about what to do when flood waters get to you. One cup of disinfecting bleach per 5 gallons of water. On areas where you can't use bleach you can get "wet & forget" to kill mold but it is about 20 bucks a gallon and use it full strenght.  To keep water from creeping up the drywall above the water line, just slash drywall with a good knife, as it is lots eaiser to replace 1/2 a sheet than a complete sheet. Your long term concern here is mold, you must prevent it from returning, and bleach works best. All areas need to dry before you close it up. It isn't rocket sicence, just so much work

  I've been through this and feel for you. It is worse thah a fire, or a tornado, just so much work..,