TAU CETI is a big, complex story with a large cast of characters (you can’t quite call them all ‘people’). This non-exhaustive list gives all of the important characters, named or unnamed.
Humans:
The crew of the Santa Maria
Jeffery Carter
Marc Piñero
Janelle Blaine
Jennifer Trent
Shelley Carsen
Henri Benedict
Michelle Patterson
Thomas Blake
Amanda Haskell
Sumin Lee
Greg Haylin
Bill Pearson
Earthlings:
Jaime McGillicuddy
Commander Chen
The Assistant Director
The Scary Monster Group (anonymous members)
San Piaz:
Aymara
José Velasco
Herkren
Aduviri
Jiampierre
Aliens:
Krangol:
Mehkon
The Law
Slerc:
The diplomat
The ship commander
The hunt leader
The youngling
Ordelif:
Tridden
Blegllel:
The Inquisitor