Nikaah & Marriage Issues

Q: What is the correct way of holding an engagement in Islam? Also, is segregation between men and women necessary in waleemah functions?

Q: 

1. What are the Sunnats and Aadaab of nikaah and walimah?

2. What is the Sunnah mahr?

Q: I had a big discussion about hurmat musaharat with a scholor of the Shafi school of thought. There exists absolutely different opinions about this issue. Would you be kind enough to provide us all Quraan aayat and ahaadith with English translations on the basis of which the Hanafi scholars give fatwa for hurmat musaharat.

Secondly, how do we define shahwat and how is it determined for this issue?

Thirdly, why is there a great difference in opinion of both Shafi and Hanafi mazhabs. 

Q: Are there any specific days or time of the day where sex is disliked between husband and wife except menstruation days? Few people say eclipse time and so on..

Q: I want to marry a second wife, do I need permission from my first wife?

Q: My husband and I did our nikah with the consent and presence of my family. But his family was not involved, neither informed about it since they were not in favor of the nikah. It's been a year now. My husband's family know about the nikah but to this day there has been no rukhsati or waleemah. Can waleema be done now?

Q: Nabi (Sallallahu Alaihi Wasallam), in his waleemah in his marriage to Zainab bint Jahsh (Radhiyallahu Anha) spent extra on the waleemah, fed meat etc.

Can it thus be said that having a big waleemah is sunnat, (without breaking any laws of sharee'at etc) just like having a small and simple one is found in the hadith to be the most blessed.

Q: I'm getting married in June Insha-Allah. When my parents were discussing the mahr, I kept a request in front of my in laws and my husband that instead of money I wanted to be gifted with a Surah from the Quran which will hold a value of living a good life after marriage and adding barakah to our life. So me and my husband will be memorizing it. Is it a valid point?

Q: In a nikah ceremony for a new Muslim couple, one male adult wakeel on behalf of bride and another male adult witness were present. Is the nikah for both valid. Later this nikah was register in a madressa with a mufti.

Q: I am married and by mistake had an affair with a guy. Now I am pregnant and that guy forces me to continue the relationship otherwise he will claim for that baby from me. Please tell me what should I do now. Here I need to clear that I am not sure that the baby is from that guy or from my husband. I seek forgivness of Allah for the sin and I pray to Allah that the baby belongs to my husband. Please help me in this issue.