In the Odyssey, are the endings really endings? Is there appropriate “closure” or “finality”?
An additional consideration is that scholars believe that the Odyssey isn't necessarily ended correctly. In other words, the best ending would be that Odysseus is back, he's retaken the house, and life is good again. Naturally, you can include reuniting with Penelope. However, you have a book that has the families of the slain returning to deal with Odysseus. In real life, the suitors' families do return and kill Odysseus and his family for revenge, so the natural question is: why isn't that included in the Odyssey? Why is the start of that conflict mentioned, but not its conclusion?
The answer is the the Iliad and the Odyssey are the only two remaining books from a collection of epics dealing with the Trojan War, and we are missing the rest, so it's quite possible that the last book, or two, from the Odyssey are actually portions of something else that was left over, and tacked on to the Odyssey due to their obvious relevance.
By endings I assume you mean the endings of each book. Each book has an "ending" of sorts; each adventure comes to a close and leads to a new adventure along the journey. The final ending is classic for its resolutions. Revenge is served hot, the enemies are defeated, the family is restored, the kingdom is secured, the goddess Athena makes her final and greatest intervention, and the romance is consummated. So the entire text is appropriately brought to close, poetically so.