I’ve recently made a plugin for a server replacement that added a Kill Everyone Campaign. Not all missions are added but most are, below are my numbers.
Prologue
Freeform Training - 83 NPCs
The Final Test - 46 NPCs
Season 1
Showstopper - 300 NPCs
World of Tomorrow - 299 NPCs
Guilded Cage - 290 NPCs
Club 27 - 294 NPCs
Freedom Fighters - 135 NPCs (add one if you want to include the prisoner)
Situs Inversus - 170 NPCs (includes Soders)
Season 2
Nightcall - 31 NPCs
The Finish Line - 300 NPCs
Three Headed Serpent - 300 NPCs
Chasing a Ghost - 296 NPCs
Another Life - 106 NPCs
The Ark Society - 365 NPCs
Golden Handshake - 138 NPCs
The Last Resort - 215 NPCs
Season 3
On Top of the World - 211 NPCs
Death in the Family - 111 NPCs
Apex Predator - 212 NPCs
End of an Era - 176 NPCs
The Farewell - 305 NPCs
Untouchable - 56 NPCs
Shadows in the Water - 176 NPCs
Bonus Missions
The Icon - 133 NPCs
Landslide - 232 NPCs
A House Built on Sand - 208 NPCs
Hokkaido Snow Festival - 169 NPCs
Holiday Hoarders - 298 NPCs
Dartmoor Garden Show - 165 NPCs
Patient Zero
The Source - 250 NPCs
The Author - 130 NPCs
The Vector - 31 NPCs
Patient Zero - 142 NPCs
Special Assignments
Embrace of the Serpent - 317 NPCs
Illusions of Grandeur - 236 NPCs
A Silver Tongue - 313 NPCs
A Bitter Pill - 112 NPCs
Will edit this message and reply when I add the rest of the missions.