One GPS is on the APM and the other is for the OSD (on screen display) unit. Gives heading and speed etc on my Fat Shark goggles.
The frame I like although it seemed a little more difficult than it should have to square the motors on the booms.
The power distribution is done on a bus theory. The big wires feed the esc's. One wire goes to a UBEC that powers the APM board and the receiver.
I have another wire that feeds power to my auxiliary lights.
My GoPro gets its power from the UBEC as well.
Power for the video transmitter and the OSD are powered from the current sensor velcro to the battery.
I need better batteries though, at full throttle it draws over 100 amps.
Hope it helps