In Homer's Odyssey are there any real differences between the message of the 1st Council and the 2nd Council, which Hermes delivers?
In the first book of Homer's Odyssey, Zeus addresses the gods about the Aegisthus' murder of Agamemnon and the revenge that Agamemnon's son Orestes would take upon Aegisthus. Athene expresses her concern about Odysseus and Zeus assures her that he will help Odysseus leave Calypso's island. Athene suggests that the send Hermes down to break the news to Calypso. Because Hermes is the messenger of the gods, it is appropriate that he deliver the message.
Although this 1st Council occurs in Odyssey 1, the audience has to wait until Odyssey 5 to hear the results of this council carried out. Because some 1500 lines have passed since the 1st Council, Book 5 opens with a return to the council of the gods.
In Odyssey 5, Homer omits the business about Agamemnon, Aegisthus, and Orestes.
In Odyssey 5, Athene does not go into as much detail about Calypso, her ancestry, or her island home.
Also, in Odyssey 5, Zeus does not give background on Odysseus' blinding of the Cyclops and Poseidon's anger at Odysseus because of this.
Another difference in the details is that in Odyssey 5, Zeus immediately summons Hermes to deliver the message of Calypso, whereas in the earlier book Athene suggested that they send Hermes.
Additionally, in the 2nd Council, Zeus also reminds Athene that she was the one who arranged for Odysseus to arrive home late and destroy the suitors:
Was this not of your own devising, that Odysseus might return and take vengeance on them all? (Odyssey 5; A.S. Kline translation)
Although there are differences in the details between the first and second divine councils, the basic message is the same: Zeus has not forgotten about Odysseus and he, at the urging of Athene, will arrange for his release from Calypso's island by sending Hermes down to deliver the message.