Stuck calipers are not an uncommon problem. The issue is whether or not water has contaminated the brake fluid, and water goes right to wheel cylinders and calipers. It also causes master cylinder and proportioning valve malfunctions and failures.
Open the hood, unscrew the cap on the BRAKE master cylinder reservoir, stick your finger in and rub it across the bottom. When you withdraw your finger the tip should not be gooey black.
A smoking rotor disc and caliper may mean they have been ruined. Not repairable. Must be replaced. Has to do with losing temper composition in cast iron.
Unless the rig was irresistibly attractively priced, myself I would move on down the line. Some rotors alone cost in excess of two hundred dollars never mind a caliper, pads, master cylinder, wheel cylinders. This thing could snowball into a Matterhorn grade avalanche...
