Hello Draconium, 
The problem is that it’s a bit unclear if “old hag” involves any kind of sleep paralysis (SP) or just the terrible one.
I am sure that the “old hag” event as the feeling described as some aggressive person over you is really really rare. I never had it myself.
Breaking sleep paralysis (SP) is easy if you stay calm,I have written several hints about it.
Here is an article about breaking sleep paralysis.
Hallucinations vary a lot depending on each person. Most people I know rarely hallucinate.
SPOILER - Click to view
I have a feeling that in LD4all, people who rarely hallucinate might even envy people who do, because it is harder to use some incubation techniques without hallucinating (example: techniques that involve HI).