Answers

A floating Luxury Vinyl Tile or Plank floor may fit your purpose.  They handle scratching well, are moisture resistant and avialible in a floating installation option.  

You would have to be extremely careful to remove all debris between the two floors as one piece of sand could cause a fair amount of damage.  Moisture that may come in through the door could get in between the top floor and cork also and would cause damage if not allowed to dry.  

Cork floors can be re-surfaced just as wood floors.  If you did experience some damage it may be repairable or you could have a re-finish option.   

Hope this helps.

Thank you