The rear bearing/hub unit is the anchor point for both the wheel and the outer end of the CV axle. If it's bad, then the wheel will be able to wiggle in every direction. And the CV axle will wiggle along with it.
If the ball joint is bad, then the entire wheel/hub/knuckle assembly will move back and forth as a unit.
If the toe link is bad, then the wheel will wiggle left to right, but not up and down.
Sounds to me like the bearing/hub unit is bad. But if it's bad enough to let the wheel wiggle over 1/2", then it should also be making some pretty scary noises when you drive it. And the back end will float around. This is a MAJOR safety issue. Because if the bearing/hub unit comes apart, the wheel can literally come off the car.
[This message has been edited by Blacktree (edited 04-27-2014).]