My question is why in Album, Artist and Complilation View does it not show the Cloud icon? You can only see these when you go "into" and Album or Artist. There you can see which songs or and entire Artist or Album are on the iPhone (cloud icons gone.) Would be nice if this could be seen at the top level.
I'm afraid I don't understand what device you are asking this question about. A computer or iOS device? You seem to be asking about this display on an iOS device, but that is not clear.
Also if I buy an album or song on the iPhone does it automatically get downloaded to my iMac?
If you have automatic downloads enabled in iTunes on your iMac, yes.