You should always have an alignment when replacing any steering mechanism such as tie rod, ball joint etc.
Since it's the lower, I think you can replace just the ball joint. Most of the time the uppers are replaced by replacing the entire arm.
Have the car checked at a wheel alignment shop.
clunking noise while going over bumps or the greese fitting on the ball joint is no longer visible or flush with the ball joint housing
Yes.
Yes
It is a good idea to get a front end alignment after replacing and part of the front suspention.
Yes
the whole upper control arm has to be replaced.it is not that expensive of a part but you will need an alignment afterward.
replace them when the have play. When replacing them, it is wise to not use a torch on certain ball joints as they will explode.Some basic things about ball joints, by Vertebratefrom the spindle. Sometimes you need a ball joint separator to do that part of the job.My suggestion is to ask "How do you replace ball joints on a "Year, Make, Model"? And hopefully someone has answered the question for that specific vehicle and year.
it could be your roll cage or ball joint might have to much movement or play and might need replacing.
You will need to remove the tire and wheel from your Oldsmobile. Remove the retaining not on top of the ball joint. Pound the ball joint out. Reverse the process to install your new lower ball joint.