Horror Fiction Help XI

Once again I'm asking my readers for help in ID-ing some forgotten horror novels. The following are descriptions which I've received in emails from folks eager to lay their hands upon tomes read long ago...

1. A demon that controls people minds in the jungles of Africa and sucks the blood of the victims through the eyes of the person with two tentacles. Leading character is taken to a village to talk to a man who was blinded by the demon but was able to survive because he had a tumor. the demon is transported to the united states before he can be killed. It turns out that the leading character is a distant relative to a hero who fought the demon a long time ago, thus the demon cannot control his mind. This was found out after he was hypnotized.

2. Remember finding this old hardcover book on the library shelf with an possibly embossed sort of melting eye on the cover. It freaked me out so I had to read it but the only memory seems to be about a some students? or a couple? that for some reason enter an old mansion and find some secret passage going deep into the earth. 

3. A child who was hanged for witchcraft in the 1700's and consequently, sells her soul before she dies so she can avenge herself upon the descendents of the ones who hanged her. She is reincarnated as a child in modern times and draws pictures of gallows poles while she is in school. Throughout the book, she lives with her religious driven father who doesn't allow her to watch tv while she carries out acts of vengeance against those around her who are the bloodline of her accusers. The book ends with her being adopted out by a family who is the sole remaining descendent she intends to kill. 

4. Some kids who go into an old house in the middle of nowhere and they know the old story about the owner of the property being a witch.  The old lady is some kind of witch and spells the souls of children into the bodies of all the old dolls she has in and around her property.  I think the setting for this story maybe the Bayou, but I can’t remember much more.

5. A guy who falls in love/gets married to a woman who has some sort of dark secret.
I think her family home is a big mansion in the woods... maybe not. Eventually it turns out, if I'm remembering correctly, that the woman is promised to the devil. So when she reaches a certain age he will come for her. There are sinister hints about her father (who is dead or missing I think) and a mysterious trunk that is eventually opened to reveal photos documenting their incestuous relationship and devil worship. It's all kind of subtle and I don't remember a lot of 'action'... not a lot of murders or gruesome scenes... just a building apprehension. 

6. The cover was a light yellow, I believe. Nothing too fancy except I think a creepy kid on the cover. Kid scared the bejesus out of me. White glowing eyes. The story had something to do with a kid conceived by insects. Insect kid. That's all I have. I think the mom gets raped by insects out in the forest, but that could just be me. I can't recall if the boy on the cover has antennae or not. 

Any help is much appreciated. I'm halfway through two different horror novels this holiday season, so should have some good new reviews up soon!