You’d think stopping in the Keys would also be ok since its US soil. Of course, that applies only to the Magic and Wonder due to size restrictions.
Since the ships are registered with the Bahamas, then any Disney ship would have to touch a foreign port between U.S. ports. So a DCL leaving Canaveral or Miami would have to stop at their Bahamian island (or some other foreign port) before and after their stop at the Keys.
Merchant Marine Act of 1920 - Wikipedia
en.wikipedia.org