I have a 2008 Ford Edge Limited AWD, It has to be towed all 4 down or all 4 up. The reason being is because of the transmission and gear box would be damaged with just 2 wheels turning while being towed.
My wife and I tow a 2008 Ford Edge Limited AWD with no problems, My wife uses the car as her everyday work car. The new Ford Edges have a push button start, our 2008 has a normal key start.