Disclaimer: I am not Rick Riordan or George Lucas.
Here are the characters in this story:
Percy Jackson - Luke Skywalker (age 16), Jedi demigod
Hazel Levesque - Tahiri Veila (age 13), Imperial demigod
Frank Zhang - Jagged Fel (age 16), Imperial demigod and general
Reyna Ramirez-Arellano - Tenel Ka Djo (age 16), Grand Admiral of the Imperial Remnant
Nico di Angelo - Kyp Durron (age 14), ambassador of Lord Vitiate
Octavian - Thrackan Sal-Solo (age 18), Imperial senator and seer
Annabeth Chase - Mara Jade (age 16), Jedi demigod
Thanatos - Xanatos (immortal), god of death
Gwendolyn - Etain Tur-Mukan (age 17), Imperial demigod and general
Dakota - Wedge Antilles (age 17), Imperial demigod and general
Bobby - Wes Janson (age 17), Imperial demigod
Tyson - Lowbacca (age 16), general
Gaea - Abeloth (immortal), mastermind
Juno - Lumiya (immortal), Queen of Tython
Neptune - Vader (immortal), King of Kamino (mention only)
Chiron - Yoda (immortal), director of the Jedi Praxeum (mention only)
Thalia Grace - Jaina Solo (immortal), Witch of Dathomir
Zoë Nightshade - Akanah Norand Goss (deceased), Witch of Dathomir
Jason Grace - Jacen Solo (age 15), Grand Admiral of the Imperial Remnant
Piper McLean - Danni Quee (age 15), Jedi demigod
Leo Valdez - Ben Skywalker (age 15), Jedi demigod
Grover Underwood - Corran Horn (age 33), Lord of the Wild
Pluto - Vitiate (immortal), King of the Netherworld
Jupiter - Zonama (immortal), King of Tython (mention only)
Mars - Yammosk (immortal), god of war
Bacchus - Ulic (immortal), god of wine (mention only)
Ella - Qwi Xux (age unknown), Omwati
Iris - Tionne (immortal), messenger goddess
Sally Jackson - Shmi Skywalker (age 45), mother of Luke Skywalker (mention only)
Porphyrion - Shimrra (immortal), Supreme Overlord of the Yuuzhan Vong (mention only)
Mrs. O'Leary - Drang (immortal), vornskr
Lupa - Vergere (immortal), Imperial instructor (mention only)
Hylla Ramirez-Arellano - Teneniel Djo (age 21), Hapan Queen Mother
Bellona - Augwynne (immortal), goddess of war (mention only)
Alcyoneus - Shedao Shai (immortal), Yuuzhan Vong
Sam Valdez Senior - Anakin Solo (deceased), ancestor of Ben Skywalker
Polybotes - Tsavong Lah (immortal), Yuuzhan Vong
Arion - Tikk (immortal), uvak
Cerberus - Tuk'ata (immortal), guardian of the Netherworld
Festus - Falcon (age unknown), mechanical dragon
Marie Levesque - Cassa Veila (deceased), mother of Tahiri Veila
Emily Zhang - Syal Fel (deceased), mother of Jagged Fel
Charon - Scourge (immortal), ferryman of the Netherland
Fleecy - Siri Tachi (age unknown), beldon
Terminus - C-3PO (immortal), guardian of Bastion
Phineas - Q'Anilia (deceased), seer
Stheno - Baritha (deceased), Dathomirian
Euryale - Barukka (deceased), Dathomirian
Medusa - Garowyn (immortal), Dathomirian (mention only)
Saturn - Sidious (immortal), Sith Emperor (mention only)
Gray - Mnah Ra'at (deceased), undead warrior
Scipio - Rancor (age unknown), aiwha
Otrera - Ta'a Chume (deceased), former Hapan Queen Mother
Michael Varus - Vilim Disra (deceased), former Grand Admiral of the Imperial Remnant
Minerva - Taselda (immortal), goddess of wisdom (mention only)
Apollo - Yavin (immortal), god of prophecy (mention only)
Hercules - (Anakin) Skywalker (immortal), god of heroes (mention only)
Grandmother Zhang - Zena Antilles (age 77), grandmother of Jagged Fel
Don - Droma (age 25), Ryn
Argentum - Chromium (age unknown), mechanical vornskr
Aurum - Aurodium (age unknown), mechanical vornskr
Nereus - Jorj Car'das (immortal), sea god
Kinzie - Shada D'ukal (age 26), Hapan warrior
Julia - Amelia (age 6), Imperial legacy
Gaius Vitellius Reticulus - Valenthyne Farfalla (deceased), Force spirit
Hannibal - Tarkin (age unknown), bantha
Ma Gasket - Mezhan Kwaad (immortal), weapons manufacturer for the Yuuzhan Vong
Lulu - Chelik (age 24), Hapan warrior
Hank - Cal Omas (age 17), Imperial Senator
Larry - Sien Sovv (age 16), Imperial Senator
Doris - Alyssia (age 23), Hapan warrior
Cato - Lord Hoth (deceased), Force spirit
Jacob - Vitor Reige (age 18), Imperial demigod
Hippolyta - Ni'Korish (deceased), former Hapan Queen Mother
Wheat - Tarfang (age unknown), Ewok
Barley - Chirpa (age unknown), Ewok
Sorghum - Logray (age unknown), Ewok
Millet - Paploo (age unknown), Ewok
Oats - Teebo (age unknown), Ewok
Julius Caesar - Jonash e Solo (deceased), former Head of State of the Galactic Empire (mention only)
Octavian / Caesar Augustus - Berethron e Solo (deceased), former Galactic Emperor (mention only)
Locations:
Camp Jupiter - Imperial Remnant (New Rome - Bastion)
Camp Half-Blood - Jedi Praxeum (mention only)
California - Outer Rim (San Francisco - Braxant sector)
The Underworld - The Netherworld of the Force
Fields of Punishment - Chaos
Elysium - Alderaan
Isles of Bless - Zonama Sekot
Fields of Asphodel - Lake of Apparitions
Portland - Ossus
New Orleans - Tatooine
Seattle - Hapes
Olympus - Tython (mention only)
New York - Coruscant (mention only)
Alaska - Hoth
Othrys - Korriban
Canada - Chiss Space (Vancouver - Nirauan)
Manhattan - Galactic City (mention only)
Wolf House - Baanu Rass (mention only)
Argo II- Millennium Falcon
Species:
Human - Human (Mortal - Mundane)
Faun - Ryn
Olympian - Je'daii
Gigantes - Yuuzhan Vong
Titan - Sith (mention only)
Centaur - Chironian
Cyclops - Wookiee
Hellhound - Vornskr
Pegasus - Aiwha
Earthborn - Rakghoul
Harpy - Omwati
Aura - Melodie
Hunters of Artemis - Witches of Dathomir (mention only)
Horse - Uvak
Automaton - Droid
Gorgon - Dathomirian
Laestrygonian - Gundark
Amazon - Hapan
Nebula - Beldon
Spartus - Zombie
Karpoi - Ewok
Hyperborean - Phlog
Gryphon - Dactillion
Basilisk - Amphistaff
Protogenoi - Celestials
Lares - Force spirit