Make sure it's not a seized compressor. If it is, replacement with new(as you proposed), along with the components you listed, is smart. FULL flush as well. Larry Bible has a lot of good info in the archives on this. An R4 (what your compressor is) is not worth rebuilding IMHO (BTDT). The only part I'd replace on an R4 is the shaft seal (with a new double lip). Anything more needed on one, get a NEW one. A good place to start your A/C education is here:
http://www.aircondition.com/wwwboard/