Yes. Any of those could be the cause.But the caliper piston and the drive in caliper guide pins have been the most frequent cause of dragging front brakes on that type Ford brake caliper. Those pins should be replaced when the pads are replaced and they should be thoroughly lubricated with brake grease. And whenever the piston becomes extended against well worn pads it tends to get cocked in the bore and jam, often making an impression on the piston that causes it to fail if compressed and put back in service.
To determine if the problem is hydraulic jack up the front end, install a wrench on the bleeder of a caliper and have someone repeated apply heavy pressure on the brakes and then release the pedal. When the pedal is released the wheel should be turned without excess effort. If the wheel cannot be turned open the bleeder while trying to rotate the wheel and if fluid exits the bleeder and the wheel immediately turns look upstream of the caliper at the hoses, proportioning valve and master cylinder for restriction.If opening the bleeder doesn’t free the wheel to turn the problem is in the caliper.