Zoro falls down a staircase and dies.
Nami finishes the map, but spills a glass of orange juice on it just as she completes the master copy. All her notes are ruined, she commits suicide.
Usopp goes back to his hometown to find that everyone has forgotten him and his childhood friend has been married and is living happily. He sinks (further) into despair and travels off, never to return. Decades later, a cracked, battered mask with prongs like the sun and a goggled front washes up onto a beaten shore.
Sanji gets his legs and arms broken, and also loses his sense of taste. He tries cooking holding a knife with his mouth, inspired by Zoro. He slips and slices his neck open.
Chopper gets AIDS.
Franky travels to China. Tries filling his tanks up with shitty bootleg cola. Contracts something awful and rusts to death.
Brooke returns to see Laboon. Laboon joyously flips into the air, landing on Brooke who is crushed into splinters. Bone shards infect Laboon, who dies of infection shortly after.
Robin gets off free just because.