Jeff Bezos, the founder of Amazon, is buying an estate on an exclusive man-made barrier island in Miami known as “Billionaire Bunker,” where he will be neighbors with a growing list of celebrities including Tom Brady, Ivanka Trump and her husband, Jared Kushner.
Bezos, 59, is paying $68 million for the three-bedroom, waterfront home, which sits on 2.8 acres (1.1 hectares),…