I think lucid dreaming in nightmares is probably pretty common, it certainly is for me. The type of fear nightmares evoke never really occurs when you're awake, making it easier to realize that you're dreaming. As for the way you're nightmares always come after false awakenings, I've never heard of that happening to anyone else, but you could probably use it to your advantage. Just get in the habit of performing some sort of reality check, like pinching your nose shut and seeing if you can still breathe through it, immediately upon awakening. You should end up doing it during the false awakenings, and end up lucid before scary things start happening. Then you can have some time to try to sieze control of the dream, and hopefully lead it away from becoming a nightmare.

As to your question, things done in a dream that you've never done while awake can be the same as they are in real life, but it's not certain. I think what they're like in a dream depends on what you subconciously expect them to be like, so how much like reality it is probably depends on how close to reality your expectations are.