Usopp, the legendary sniper of the Straw Hat Pirates, would have died along with Kaya, as there was no way anyone in Usopp’s village would have been strong enough to defeat Captain Kuro. Usopp would have likely giving his life to save Kaya.
Sanji, the future cook of the Straw Hat Pirates, would have remained a cook at the Baratie and would have easily been killed by Don Krieg, when the pirate captain attacked the restaurant. Without Luffy, there would have been no way Sanji could have survived.
More on page 3.