Do you have warranty coverage on your Edge? The leak/drip is either an axle seal leak or a leak from the PTU vent. In either case, you need to have it serviced ASAP. Will definitely kill mileage. If out of warranty, could possibly have the PTU modified so that you can flush/change the PTU fluid easily. Look for posts by the_natrix to explain further.
Brakes do tend to be noisy after the Edge has been sitting for a while, and you have had some COLD weather in your area. Changing out the pads/rotors with non-Ford parts usually resolves that issue. Keep an eye on the brake fluid level, that will tell you if there are any leaks to be concerned about. If a caliper is dragging, you can usually feel the difference in wheel temps right after hard braking, though I don't know due to the temps in your area. That would cause decreased mileage as well.