Treasure Island/WMG

Dr. Livesey is The Doctor Himself
Well, if he was Merlin, this can't be too far a stretch.
 * Dr. Livesly shoots people, so it can't be.

Long John Silver's pirates are secretly Patriots agents traveled back in time
they sent back in time to Captain flint's treasure, and the Patriots ordered them to kill John Silver if he helped out Captain Smollet

Long John Silver eventually invested his share of the treasure to open a seafood restaurant
Obviously, it became huge later on. You may have even eaten there.


 * Heck, this is what he was doing when he's introduced.