Brakes locking up
Just throwing this out there.
Have you verified that the rear shoes are on correctly
Have you verified that the adjusters are on the correct sides. The adjuster should work by applying the brakes when in reverse, that causes the lever to lift and fall back onto the adjuster wheel, causing it to turn a little if it needs to. If they were on the wrong side of the car they would adjust tighter every time you applied the brakes moving forward and become too tight.
How do you get the rear brakes to release? For more than a few feet?