Think of it as 4 different sensors, as 4 different slave devices on the I2C bus.
They happen to be on the same board, but that's just a coincidence.
So you need 4 different interface software for the 4 sensors.
The I2Cdev lib happens to have libraries for all 4 of them, and the libraries will work together.
So there is no configuration of the GY-80. You have to initialize the 4 sensors. The libraries will do that for you.
The board has a voltage regulator and level converters and pull-up resistors on all sides. You can connect it to a 5V Arduino without anything else.