The joke they should have put in
Not everybody would get the joke, but I could not have resisted making it if I made the movie.
I would have had Gonzo play Squire Trelawney.
And the they could have found a tribe of Cornish Hens on the island (instead of boars) who became friends with with Trelawney.
Then, in the final battle, with the pirates, Long John Silver could have raised his cutlass to kill Squire Trelaney when a spear pinned his sleeve to a tree. Silver would look around and he and the audience would see hordes of the Cornish Hens waving spears.
And the Cornish Hens would say: "If Trelawney must die, here's twenty thousand Cornish Hens shall know the reason why!"