Queen Paolana Billups was the female monarch of Hysperia and mother of Andarithio "Andy" Billups, who was the crown prince. He had renounced his title to join Starfleet, but his mother refused to accept that and kept trying to trick him into triggering his ascension onto the throne. Her ship was called the Monaveen.
Ambassador Grubdin was a Pakled male. He was also the ambassador tasked with greeting Captain Freeman and her away team when they came to Pakled Planet, though he (and all the other Pakleds) actually believed she was Captain Janeway of the U.S.S. Voyager.
Malvus was a male Mizarian shopkeeper on Starbase 25. He and Mariner knew each other, from when she was previously assigned to the station, and he no longer considered her a friend because of how she’d once stranded him on Ceti Alpha IV.
A species that would duplicate whenever they felt threatened, as a defense mechanism – but since they were quite sensitive to criticism, nearly any embarrassment or perceived criticism could trigger this. The only way to get their duplicates to reintegrate themselves afterward were to then make them angry.
Class of Federation starship. It was specified at the exclusive Starbase 25Starfleet Captains' Party that entry was restricted to captains of ships of this class and above, implying that the U.S.S. Cerritos, being a California-class ship, was in a lower class than was allowed.
The location of a series of trade negotiations, for which the U.S.S. Cerritoswas escorting a Doopler emissary. After the negotiations, there was a massive (and exclusive) party that Boimler and Mariner spent all day trying to crash. Mariner used to be assigned to this station at some point prior to the Cerritos.