The only problem with this 'report' is that this land was never owned by Disney. It was owned by a German investor who persuaded Premier Cruise Lines to use the area as a day island for the Big Red Boat, which was licensed by Disney. It looks like because the Disney name was attached to the Big Red Boat, people assume that the boat owned by Disney, and so was the island.
Instead of googling Disney and Baker Bay, I googled Baker Bay and Big Red Boat. There were some sites that had a better explanation of the island's use. Some sites will say that it was Disney's islands, etc.
I did the BRB back in 1990, and there wasn't anything Disney that I can remember about that island.