Why is my rear suspension squeaking/sound loose

FIrst problem I spot is impact tight. Need to torque to specification, too tight can cause squeaking, too loose can cause squeaking or knocking. You mention the rear, but only talked about the front control arms and rear shocks. Only thing in the rear that would squeak would be the swaybar links, nothing else. Up front, there's a lot that will squeak. Ball joints, upper, and lower. Upper and lower control arms. Swaybar bushings, and styrofoam inside of bumper. When you replaced the upper control arm, did you replace the ball joint too that presses into the control arm? If so, was it a greasable ball joint that has a Zirc fitting?

*****Forgot the rear swaybar bushings, those could squeak as well as the link.