1.It sounded like you were actually lucid, you just didn't have any control. In lucid dreams you will have varying amounts of control; some you'll have quite a bit, others you'll have none.
2.The guy could have been anybody. From the context of the dream though, he might have been a dream guide-a special type of dream character that helps you with dream control/stabilization throughout your dream(s).
3-The RC's most likely failed because you subconsciously expected them to fail. There's little you could do about this except expect your RC's to work when you do them. Even if you do this though, not all RC's are 100% reliable. The nose plug is my favorite but even that one has failed me a couple times. If all your RCs fail in a dream you should check out where you are in the dream and where you've been the last couple minutes. Basically, ask yourself if the dream has perfect waking life vividness and if the events that have occurred the last couple minutes are reasonable. If you do this, the majority of the time it'll be become obvious if your dreaming or not.
4-In order to have more lucidity and control, whenever you can, try to take a moment to gather your thoughts upon becoming lucid. Before going to bed, think about what you want to do in your lucid dream and try to recall these goals upon becoming lucid. You could come up with a routine upon becoming lucid, saying something "I'm lucid. (deep breath) What are my goals?"

Good luck and have fun!