The whole hag thing reminds me of something my little sister told me once. I was away at college at the time and she was still in high school. She told me that she woke up in the middle of the night to see a "very scary looking old lady with white hair" floating in front of her face--just the lady's head. We still have a bunkbed in our room (our house is small, and my mom had 5 kids) and she was on the top bunk, sat up screaming, and nearly fell out of bed. Next thing she knows, our mom is in the room asking what happened and why she was screaming. She told my mom, and she just told her to go back to sleep--it must have been a dream.
Another thing is something I read a couple of days ago online when I was looking into all this stuff because I was bored. I was just looking for haunted places around where I live in Ohio, and I came across a message board that talked about white noise helping EVPs, or even making it so people hear things like voices or music with just their ears due to the white noise (i.e. hearing someone talking until you turn off a fan).
This reminds me of something I always used to hear when I was little, and sometimes still do when I'm sleeping at home, especially when the ceiling fan is on. I would hear a man, or sometimes woman's, voice, but I could never understand the words...it sounded very much like a news broadcast just in the way the words would flow, so I would just think it was my mom up late watching the news. However, there were a couple of times where it was just getting really annoying to me, so I would crawl out of bed with the intent to go to the living room and ask my mom to turn it down, but when I got to the hallway, I would see that all the lights were off, and so was the tv, and my mom would be in bed asleep. As soon as I would crawl back in bed, it would start up again. Has anyone else ever had that sort of thing?