Spoiler alert.
There are 31 known talking heads/characters who appear on the relationship list. According to the addresses in CE, there's a three-entry gap between Cricket and Kukul. Later on, there's a one-entry gap between John Sheppard and Rose, but that was a duplicate value for Sheppard during an earlier build of the game.
Chairman Brass
Emilia
Cricket
[unknown]
[unknown]
[unknown]
Kukul
Apis
Fafnir
Lois
Olaf
Marco
Calvin
Orion
Sigurd
Spencer Rice
Kevin A
Captain Mustaparta
Pim
Solanum III, The High Priest of Orth
John Patson
Sapoboi Rodrigues
Chief Guard
Huli Kitsune
Nikuban
Jacob Fulier
Dolland Truffle
Lipas
Samantha Stone
Eliah
Fiston Diputtan
Richard Weaver
John Sheppard
[unknown]
Rose