The amp definitely is as when you fold down the seat behind the driver, you will find a b&o branded amp. When you say the head unit, are you referring to the 12in the main display, because if you are, it is a ford product? If not, I, unfortunately, do not know about the head unit.
For the first question, I'm not exactly sure but my 7pin is always active when the truck is on (idling or on battery power) but in terms of accessory power that may be something else needed to be hooked up separately.
And for the squatting, you will definitely see the difference when you level...