Both Zoro and Kaido’s characters are built around strength, both of them have similar thecniques: Kaido has Three Realm Ragnarok and Zoro has Three Thousand Worlds (Both of them use spinning motion in their thecniques).
Both Kaido and Zoro have Dragon theme to their characters. Oda even said that if Zoro had a Devil Fruit then it would be Kaido’s Devil Fruit.
Both Kaido and Zoro are famous alcoholics. In many ways they have similar personalities etc.
Here are the parallels between Usopp and Shiki:
Both Ussop and Shiki offered someone stronger than them to join their crew: Luffy and Roger.
Both Ussop and Shik are kind of a joke in their crews, both of them have similar personalities.
Both Shiki and Ussop are famous for their huge fleet/ followers.
The similarities between Yamato and Big Mom are obvious so I’m not going to spend my time on it. But if Yamato doesn’t join the crew then just replace her with Nami.
The hints and foreshadowings for Sanji’s Conqueror’s Haki.
There are two qualities that Conqueror’s Haki users have: it’s either the ability to scare people like Zoro and Kaido or the ability to gain followers even if you don’t want them just like Oden and Luffy.
So, has Sanji ever shown one of those qualities? Yes he does. Sanji has many times turned his enemies into his followers. For example:
