The Goonies find a coin in the wishing well with the portrait of Kennedy on it, making it a Kennedy Half-Dollar. Who throws half-dollar coins into wishing wells?
Rich snobs with money to burn. AKA, the usual fare of the local Country Club.
Why does One-Eyed Willie have an eye patch? Based on the fact that there's bone underneath, he didn't lose the eye, he was born without it.
Because he wanted people to look at him and instantly realize that he's a force to be reckoned with. There's no better way to do that than to have an Eyepatch of Power.
Spielberg has openly admitted that the most iconic scene in Raiders of the Lost Ark was taken from Carl Barks' Uncle Scrooge comics — has he or anyone else involved ever admitted the same about the entire premise/plot of this film?