When I needed to replace a stud on my front wheels I was also concerned about bearing damage. The responses I received were to not be concerned and I hammered them out and haven't had any issues.

With respect to doing the rears, I think that once you remove the disk you will see the best way to turn the wheel to get them out. With regards to rotating the wheel, you can rotate the rear wheel with the car in neutral - even if one rear wheel is on the ground.

On a safety note, you should NEVER work on a car when it is supported by a jack. When jacking up the rear, place blocks in front and back of the front tires to keep it from rolling. Jack the car up and support it with jackstands.