These are all the characters that I know of to appear in the story.

Percy – Penny

Annabeth – Anubis

Grover – Grace

Tyson – Tyra

Thalia - Theo

Nico – Nikki

Will – Willow

Jason – Jessy

Piper – Peter

Leo – Leah

Reyna – Ryan

Frank – Fay

Hazel – Hayden

Octavian – Octavia

Dakota – Darcy

Bobby – Bobby