I'm guessing it won't make a difference as to the requirement of both in the cabin having the same package. On paper, they aren't officially switching cabins, just getting the ability to open a different door.
What port? If it's a US port, everyone needs to get off to zero out the ship.
However, I doubt anything will be open as the crew will be doing deep scrubs of everything.
I would drop him off at the luggage drop off, since you go there first anyways. Tell the people directing traffic you have a rear ramp and they should be able to accomdate you.
The ship will be "dead heading" from Miami to Orlando. Not only will you need to pack up, then leave the ship, you will need to find your own way to Orlando.