I hear the term overdone used and feel like I understand it some what when applied to headpieces. My question is does it apply to all aspects of dogs. For example, rears and fronts.. I see pictures of labs with severe angulation in the rear or a forechest that is extreme and wonder if the term overdone is correct? Is there a better term?

overdone to me can mean either the whole dog, or just the head. In some cases you hear "the heads overdone" which means just the head is too much. Sometimes the head doesn't fit the body. I had a dog that had too much head. It was too wide, muzzle too short, and just big. Otherwise it would mean the whole dog is overdone. Too much bone, heft, width, almost sloppy is my interpretation.

I like a clean neat dog myself that looks like it could work if desired, but still has type, coat, bone, and melting expression!

too much rear angulation would be called just that--
"overangulated". That wouldn't mean the whole dog is overdone.

Overdone means too much whatever. We have been using that term for decades and you know you can't teach an old dog new tricks.