>>I don't know FL permits work, especially for indigos, but I would imagine at minimum they would have to get their current permit amended to state the number and sex of the animals they have or intend to have. They may be able to do that after they receive the animal. Again, only a general idea.
The federal permit is for interstate transport, and really applies to commerce. If you are selling or trading the snake for goods, they will need to acquire the permit from the USDI/FWS. If you are donating the snake (no money or trade) then you can ship it without the permit.
It might be a good idea to find and speak to the person/biologist in charge of issuing their current permit and find out for yourself what are the state requirements (paperwork, etc.) for them to acquire this snake.
I will not discourage you but it is a gamble to send captive animals to customers in the states where the animal receives local/state/federal protection. Cross your i's, dot your t's and watch where you step!
good luck,
daveb