In this episode, we get the full names of all the guests in the hotel:
The reason for renaming the guests with proper names is to build on the realistic tone established in the second season. This was hinted at eariler in the season.
List of Guests:
Omni as William 'Will' Omninus Trondion
Sub as Samuel Unican Bravtos
Ultra as Anthony Armando Anderson
Omi as Oliver Maximus Ivakov
Jack as Jack Doogorn
Brandon as Brandon Grundare
Speedy as Cassie Stallion
Lego as Malcolm Plemons
Tyran as Brett Lipton
Drillo as Dill Walkers
AB as Alexander Cloon Dämon Barnsworth
Scoot as Lewis Tinkers
Nate as Nathaniel Dumstrong
We also get the full name of Vicki: Vicki Olivia Demple.
Charles' full name was established in the last episode as Charles William Butler.
Kross' full name is revealed to be Kross Lucifer Monday.
The Warden is revealed to be Sif Hunderson.
We also get introduced to three agents of the Wikia Agency of Investigation:
Yopo as Christopher 'Yopo' Rider
Mig as Miguel Rivers
Alan as Alan Nomaly
Dr. Lucius Sines is in fact the alias of Daral Scidran, the author of the novel A History of Wikia Island. The book was last seen during 1989 in Chair of Mountain Terror, while it was last seen during 2014 Wikia Island in the conclusion to the riddle in Under The Sea.
The Last Known Whereabouts was a nod to both Whodunnit and the song "Writing on the Wall" by Sam Smith.