Conditions for the validity of Nikaah

Q: Can a woman suffering with anal fissures get married? Will anal fissures in a wife affect the husband and wife relationship on their first night of marriage?

Q:

1. If a man does the ijaab of marriage in front of two witnesses but the woman does not say the qubool, will there be any marriage?

2. If a man says to a woman‘you are my wife’ in front of two male people,will it be considered a marriage?

Q: If a girl says to herself in front of many male people ‘I am married’, does she become married?

Q: If a girl says to herself ‘I am married’ and no one can hear her, does she become married?

Q: In Islam, is it halaal to get married under 18 but by Law its illegal to get married under 18?

My question is: Can I do nikah but not get married by Law (I'm under 18 and the girl is under 18 too and we are in Europe... In my country like most of the countries its illegal to get married under 18)

Ma Sha Allah im 17 and she is 16 which means we have to wait 2 years... We both are muslims Ma Sha Allah, and she has a "wali" and everything else. Alhamdulilah its okay but that is the one and only problem.

Q: A girl and a boy used to like each other. One day, one of the friends of the boy asks the girl ‘Do you marry Zayd (the boy)?’ The girl replied ‘Yes’ in front of many people. Are they married now?

Note that the boy did not say anything nor appointed his friend to conduct the marriage. The friend just joked with the girl.

Q: Does a nikah done as a joke (just for the sake of fun) in a friends gathering without the presence of the wali, become valid?

Is it valid when the girl says yes just because of peer pressure of acceptance in a group and without having the knowledge of the sensitivity of this subject/issue of nikah.

Q: My question is regarding my marriage. When I met my husband I wasnt paying much attention to religion so we married in court as civil marriage. My father and mother left me alone in another country so I didn't have any wali present on the day we got married. Now since I learned more about Islam and I am concerned, I would like to know if our marriage is valid?

Q: If a girl says to a man that you are my father in law, does nikah happen between the man’s son and the girl?

Q: If a girl and boy gets married without any witnesses, the nikah is invalid. In this case, does the boy have to divorce the girl or there was no marriage in the first place?