Nikaah & Marriage Issues

Q: Is there any excuse for committing zina? I'm suffering from different kind of mental diseases and I feel like zina would help me overcoming them.

Q: I am about to turn 19 and live in Canada. I am baligh since the age of 9 (which means I had my periods). I am currently in college and I like a guy. I want to do nikkah but my parents don't allow nikkah at such a young age specially till I don't complete my studies which has around 5 to 7 years.

I am scared of doing something haram (like zina) and I want to turn it halal as soon as possible. I have the witnesses, I am completely sure about this marriage since the guy belongs to a good family which is also religious and fulfils its Islamic duties. But I recently heard that nikkah without the consent of wali is invalid.

Now my question is, in what Hadith or verse of the Quran is it mentioned that the father should be wali? Can I make an imam my wali? Or can I conduct my nikkah without a wali while fulfilling other conditions such as witnesses, and haq mehar.

A detailed response over this matter for better insight would be appreciated. 

Q: What is the ruling for parents towards upbringing of their children.

If children are not on the right track, upto what extent is it permissible to be strict or authoritarian towards child-raising? Kindly explain in detail.

Q: Such child, whose father is a descendant of Prophet Muhammad (sallallahu alaihi wasallam) through his mother, is he considered to be descendant of Prophet Muhammad (sallallahu alaihi wasallam) or not?

Q: I am 24 years old and I have been addicted to pornography and masturbation for almost 9 years now. I know Allah is very angry with me and I want to get married but I do not have financial means for marriage and my parents are also not taking my problem seriously. What should I do in this situation.

Q: What if someone is so addicted to masturbation that the person is not ready to stop doing it?

Q: Is it permissible to attend a mendhi ceremony/party or is it imitation of non-Muslims?

Q: Is marriage considered as an ibaadah?

Q: I did ijab o qbul without mehar and wali and without witness 8 years ago. There was no physical relation but I realized it is wrong. I left that boy now and my father is getting me married to my cousin. Should I get married to him or tell my father about the nikah 8 years ago?