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Actually No Some Middle Names Or Nicknames Have Been Revealed Though.
With The Exception Of The Parody Of Paris Hilton (Dakota Milton).

actually, Harold also says his full name at one point too (Harold Norbert Cheever Doris McGrady V). Cody's is Cody Emmett Jameson Anderson, told to us by Sierra, as Miss Honeyblood said.

Found these names over here, not sure how accurate this is as most of them were fan made, but they're kinda cute.

Beth Yentsten
Bridgette Summers
Cody Emmet Jamieson Anderson
Courtney Satella
Devon Joesph "DJ" Benson
Duncan Tarun
Eva Garren
Ezekiel Miller
Geoff Algolen
Gwen Ingrid
Harold Norbert Cheever Doris McGrady V
Heather Kasuga
Izzy Connelly
Justin Batofel
Katie Uratu
Leshawna Olongala
Lindsay Top
Noah Sterecra
Owen Waterflower
Sadie Unda
Trent Cooper
Tyler Kenard

*edit* Heather's last name doesn't fit because I recall seeing Heather's video message by her parents and her dad is caucasion therefore the japanese last name is inaccurate. idk if I'm getting my point across lol