The following are all required to obtain 100% completion:

All Missions Completed
Ken Rosenberg
Avery Carrington
Colonel Juan Cortez
Ricardo Diaz
The Vercetti Estate
Love Fist
Biker Gang (Mitch Baker)
Umberto Robina
Auntie Poulet
Cherry Poppers Ice Cream Company
Kaufman Cabs
The Malibu Club
The Film Studio
Pole Position Club
The Printworks
Boatyard
Sunshine Autos
Phil Cassidy
The Game's Last Story Missions

All Side Missions/Odd Jobs
PCJ Playground
Trial By Dirt
Test Track
Cone Crazy
All 4 Chopper Checkpoint Missions
RC Car Race
RC Plane Race
RC Chopper Checkpoint
All 3 Stadium Events
All 6 Street Races
All 5 Assassinations Complete (Phone missions)
Over 45 Points at the Shooting Range After "Shootist" Mission (Gaining the quick reload ability)

All Real Estate Owned
El Swanko Casa
Links View Apartments
Ocean Heights
Hyman Condos
1102 Washington Street
3321 Vice Point
Skumole Shack

All Assets Generating Money
Cherry Popper Ice Cream Company
Kaufman Cabs
The Malibu Club
The Film Studio
Pole Position Club
The Print Works
The Shipyard
Sunshine Autos

All 15 Stores Robbed
Corner Store - Vice Point
Dispensary Plus - Vice Point
First Jewelry Store- Vice Point
Gash - North Point Mall
Music Store - North Point Mall
Second Jewelry Store - North Point Mall
Hardware Store - North Point Mall
Bunch of Tools - Washington Beach
Ryton Aide Pharmacy - Little Haiti
Pharmacy - Downtown
Third Jewelry Store- Downtown
Deli - Little Havana
Doughnut Shop - Little Havana
Laundromat - Little Havana
Screw This - Little Havana

All R3 Missions Completed
Vigilante - Level 12
Firefighter - Level 12
Paramedic - Level 12
Taxi - total of 100 Fares
Pizza Delivery - Level 10

Acheivements
All 100 Hidden Packages Found
All 36 Unique Jumps Completed
All 35 Rampages Completed