Beatles - Octopus's Garden Lyrics Meaning

The first line, 'sea' is a person or an initial.
The second stanza first line, 'come and see' slurred is 'come in see', so it is a sexual reference.

The guy with the hat is the 'ring leader' or 'introducee' with the connections to get the guys out of the lime light or yank them off the stage with one of those canes but not with the rounded end you might see in a cartoon, but rather something much easier to hold on to.

The 'cave' is a rememberance of times past and a destination as if they knew where they were headed from a certain point in their lives. They hoped or wanted to share what they had learned, but simplified and said we are going to be alright, as if to hold without holding what is intangible and inviting others to at least consider the possibilities.