preparing to do some major work to the 300E...

[WANT '71 280SEL]

Within the next couple weeks, I plan to replace the rear lower control arm bushings and serpentine belt tensioner.
My main question rests with the replacement of the belt tensioner, it's making a noise and the pulley is also making some noise, so I want to replace them both. However, I read that the pulley comes with the tensioner, but what other parts do I need to replace when doing this? For instance, does the spring wear out when the tensioner does, do I need to buy any other separate bushings or parts to complete this job so I can do it all and put ir right back together without waiting for parts?
Regarding the rear control arm bushings, what else do I need to buy except for the inner and outer bushings? I've already replaced the other links, but do I need to replace that ball joint in the arm or are there any other parts I should replace?
Thanks
David