Hi mate welcome to the forum we will do it a question at a time , the little servo plug with a loop of wire this is the bind plug
The KK gets its power from the ESC on motor 1 pins this will then power the receiver through the KK board
If your going to switch self levelling on and off by the transmitter then yes connect aux up to ch5
Batt on the receiver is if you want to use a BEC to power receiver and servos more for planes or helis
Bind is where you plug in bind plug ( the servo plug with the loop of wire ) then power up quad then transmitter in bind mode ( depend on transmitter how to bind)
Yes you can take a wire for the power dis board to the kk( now if you have the kk2,1 or newer you only use a pos (+) wire to the KK DO NOT use the neg (-) it will burn the board out then your need to set up the voltage alarm
Seeing you have the KK your need to flash it with steveis1.8s1pro this is more stable than the hobby king firmware ( loads of people have crashed due to the firmware so we flash to this steveis code
Also the 2 small pins on the power dis board is used for lights etc so it is easier to just take the battery voltage sensor wire from the pos battery connection on the dis board