Do you have a angle finder, compass?
If so measure the pinion angle and driveshaft angle and let us know what you find yours are, if you don't have one or can't borrow one go get one (beg, borrow or steal one ) and check your pinion and driveshaft angles with the car on the suspension like it driven
In the sideways pictures of your driveshaft and pinion U joint is the rear end on jack stands or is the rear end hanging down on the cars rear suspensions?
Me thinks your driveshaft is to short The yoke needs to be in more when the car is on the suspension, so if it is not on the suspension in your pictures ignore this comment