If you want to save IO port, BLK backlight can not be connected. The system has been designed to illuminate the backlight even if it is not connected. If you need to turn off the backlight, you need to connect BLK to low level or directly to ground.
MISO is the output signal of the screen. If you do not need to read the information of the screen, this pin can be disconnected. A minimum of 4 IO ports are required to operate.