I haven't quite figured out what the relationship to REM sleep is yet. There are two areas of the pons that switch it on and off and I think damage to them causes the array of symptoms.
Cataplexy is when you go into REM sleep while conscious and your body loses all muscle control like it's supposed to when you're asleep. This is the behavior most people associate with Narcolepsy but only about 20% have it.
RBD is when the body is asleep and in REM but doesn't shut down the signals to the muscles. So you move or walk or talk in your sleep.
The other thing you mention is called Sleep Paralysis. It occurs when falling asleep or waking and you are conscious but cannot move. I had this during nap attacks. I couldn't move until I was done "sleeping it off". Then I would wake up with something like a hangover, I guess dizziness isn't the right word.
Another symptom is hallucinations. A lot of PWN have vivid hallucinations upon dozing or waking, but mine were always limited and mild. Kind of a psychedelic screensaver eminating from my optic nerve when my eyes were closed. Moving pulsing shapes or waves in shades of light and dark.
Vivid dreams are common in PWN. I used to wake up in the morning and have to spend time convincing myself the dream wasn't real. That I wasn't really mad at my husband or really hadn't done something stupid or whatever. Those days are gone though, I think I killed off the REM cells too. I barely dream at all anymore.

I believe all of these symptoms can be explained by antibodies attacking the sleep centers of the brain. The specific manifestations depend on which areas have the highest concentrations of antibodies clogging them up.