@Rachelle95 Be tough. It is very good of you to host the people who have come to help, but this work crew cannot take advantage and cause you difficulty. Contact the original booker -- let him know that the reservation will be cancelled unless you have a list of the persons who are staying - NAMES and phone numbers, especially that of the group leader. Ask for the license plates of the vehicles that will be parked on or near your property. Make sure that the original booker knows that a third party booking is not allowed -- why is he not present? You can cancel the reservation just for that reason.
I am licensed for a certain occupancy. Are there zoning regulations that apply to your property? If you can only host 6 persons, let the original booker know that the crew is jeopardizing your licensing and that any penalty that you are assessed will need to be paid by him or by the group leader who is breaking the law. They may be very well intentioned, but they cannot cause further damage and distress through their actions.
Much as I would like to say that AirBnB may resolve this, it is really on YOU to be in charge of your property and who is permitted to stay. A hotel/motel would not tolerate this over occupancy, and neither should you, even in light of the current situation in Florida.