Suffering from evil thoughts about Islam

Q: The stage that a person is going though nowadays is extremely sad. He is suffering from the evil and bad thoughts about Islam and Allah. He told that he wasn't like this before in his life. When he was asked about how it happened, then he told that one day he went to the graveyard and soon after he came back home, he started suffering from that same evening. He sometimes think that Allah Almighty has given him a punishment but he still offers a lot of supplications in order to get rid of it. Is it a sign of jinn possession because he sometimes get so much evil thoughts that he starts beating himself. Or it is a sign of blackmagic or a punishment or a test by Almighty Allah? 

Getting married without one's parents consent if one fears falling into sin

Q: A person asked his parents to let him get married but his parents refused him even though that person was earning good and has enough money to afford all the expenses. That person was in fear of committing adultery. He asked his parents many times and even one day he told his parents the reason why he wanted to get married. His main reason of getting married was to stay away from haraam but his parents ignored him. He was very upset as his parents refused him. He contacted a few women in order to commit a sin but he immediately realized that he was about to make a huge mistake in his life and he repented and then refrained from committing such an act. He didn't committed zina. He stood steadfast and kept remembering Allah Almighty. He wanted to hide his sins and he wanted to confess only in front of Allah Almighty. What to do if the authority asks him as he didn't committed adultery physically? He's ashamed of talking to such women by text messages and he realized that it is a sin. He has already repented from it. What are the rulings of Islam as there was a talk of committing a sin but refrained and didn't committed it physically?

Watching videos on YouTube

Q: I read one of your fatwas entitled “Nose surgery to straighten one's nose” where someone asked a question mentioning watching a YouTube video of some Shaikh. As you replied to the answer, you also added that “ Viewing YouTube videos is impermissible. If you had viewed it, then you should make taubah and refrain from repeating this sin in the future”.

I have a small question, rather request a clarification whether it is a sin viewing any video (including of Ulama) or particularly those illicit immoral videos.

Giving the buyer a gift for purchasing over a certain amount

Q: A website is selling books at a discounted price. Whoever buys books for more than R250 gets a free bookmark. Whoever buys books for more than R750 gets another book free. Whoever buys books for more than R1499 gets free home delivery.

I want to know if transactions like these are valid where the seller gives a gift if the buyer buys products of a certain amount of money?