2000 Dodge Intrepid valve noise

My daughters 2000 Dodge Intrepid has what seems to me to be a rocker arm rattle. If after I get this valve cover off and discover a collapsed rocker arm slack adjuster or broken valve spring. Can I replace only the broken parts such as the slack adjuster, rocker arm or valve spring or do I need to replace all of them for that valve head bank? Also. Do I need to use the special valve spring compressor or is there another way. Those fixed bar compressors are hard to find. Lastly are these slack adjusters prone to collapse?