bte2 could probably answer your questions way better as he is a working dog trainer.
I believe obedience is definitely a couple of those things you mentioned, I guess my definition of obedience is your dog tuned into you and listening to all commands and ignoring any type of distraction. I think there are levels of obedience, what might work for a pet owner would be completely different from a working dog owner.
Take for instance walking backwards, for a pet owner it could be construed as a "trick", but a police dog might need to do that in a real world application. I guess it all depends. lol. Personally I love training anything, because it keeps his mind stimulated. We are always trying new things.