My idea of the crew timeline (so far).

1 - BS meets Lily and the two of them begin traveling together because Lily wouldn't leave a child alone.
2 - Cedric meets up with Isuza, pays her debt off, and hires her on for the Red Rum Pirates.
3 - BS and Lily meet Cedric, who hires them aboard the crew and takes BS under his wing as a first mate.
The rest of the crew joins between these times, possibly Dirk first as a stowaway when Cedric picked up BS and Lily.
4 - Caesar is picked up out of the ocean and recruited.