When I heard that the rear axle had a drum brake (Inside the disks) on both sides of the axle, that was not what my experience. I had something similar happen a few years back. The hand brake drum is on the rear passenger side only, on my 2007 6MT. We had temperatures just below freezing, low 30's. I had just washed the truck and parked it inside the garage. Next morning, it wouldn't move in Reverse to get out of the garage! Obviously, the dealer wanted it in his shop, and I didn't want to drag it out of the garage with the wheels locked up.
I know there wasn't anything broken since I had less than 30,000 miles on it. I rocked it back and forth in 4H (not 4HL) and no dice. Then I stuck it into 4L and did the same. I think the fwd 1st has a lower ratio than the reverse, since that is where I thought it had most torque moving. In my 4th or 5th attempt, I got desperate, even though I had 18" in front left in the garage. Then "BOOM", it broke loose and I stomped the brake.
That drum brake rusts easily from the inside, and with a little ice, binds up like this if the brakes get wet. I then drove around the neighborhood in 3rd very VERY delicately applying the hand brake, to clean off the drum. Initially, it started really jerking the truck around but then got a lot smoother and manageable.
Now I just leave it in gear and don't use the handbrake overnight. Lesson learnt.