This episode doesn't feature Stewie, Brian, Meg, or Chris.
However, there is a cameo of Brian as a baby, during Peter's story, in the window of the Pet Shop when he exits to go to his apartment.
The scene of the shark knocking on the door in Cleveland's raft is a reference to an early Saturday Night Live sketch about a "land shark" who would knock on people's doors and trick them into letting him in.