The 74HC08s are for driving the LEDs on the board (the inversion of the respective SCL lines). About 2 or 3 mA per LED. Pop the LEDs off with an exact knife to save the power. But it's not much as the only take current when they are on, which is not often.
Read the specification to see how to set the jumpers for various power voltages on each bus. It's all good!