How to connect four monitors to a 15-inch MacBook Pro?
Yes, the 15” MacBook Pro supports “Up to four displays with 3840x2160 resolution at 60Hz at over a billion colours” in addition to the built-in display. You don’t have to reserve a port for power, you can run off battery, or find a display that will deliver power to the MacBook Pro. Or you can daisy-chain the displays, and run one of them by connecting it to another display and not directly to the MacBook Pro.