Opening scenes of the Liverpool quayside included one of the ruined Maria de Gloria slave ship from season two.
No Englishman would have used the phrase 'federal' government. In Britain it would have been the Crown or the Commonwealth. Bad writing.
The singing fish are not found in South America, but rather in Panama. It is really the Bocon Toadfish that sings.
It is unclear if Captain Webster was left in Lisbon.
Daniel and Elizabeth's son is not seen, and must be about 10 or 12 years old by now.