Those women with whom nikaah is permissible

Q: I am writing to seek your guidance on a family matter concerning marriage eligibility in Islam. 

I am considering the possibility of proposing marriage between my daughter and her first cousin from mother side. However, there is a specific detail that we need to clarify: the boy's younger sister is also our daughter's radaai sister (sister through breastfeeding). 

Given this relationship, I am unsure if it is permissible for my daughter to marry her cousin. Could you please provide clarity on this matter according to Islamic principles?

Q: Is it okay for a Hanafi female to get married to a Shafi male?

Q: Is it permissible for a girl to get married to her real sister's milk brother?

A lady named "Aisha" breastfed Muhammad who is her son, and Fathima - who is Aishas sisters daughter.

Fathima has a sister named Zainub, who has not been breastfed by her Khala (Aisha).

Can Muhammad, who is Fathimas milk brother, marry Zainub - who is his milk sister's real sister?

Q:

1. If a female conceived a baby from her illegal relationship before nikaah and married the same male afterwards, will the nikaah be valid one?

Does it have to be repeated?

2. If the conceived female married another male instead of the actual father of the fetus (hiding the matter), will the nikaah with the pregnant female be valid?

Q: In Islam, is cousin marriage allowed?

Medical science says that cousin marriage is wrong because it causes disabled children. Yes, there are many cases where children are completely fine but there are many cases where children are disabled because of cousin marriage.

My Conclusion: cousin marriage is risky.

Please advise me whether we should do cousin marriage or not? If your answer is yes then how can we overcome this risk?

Q: Can my father marry my mother in-law?

Q: If a girl calls a boy brother and the same boy calls the girl sister again and again in a conversation, can they later marry one another or not?

Q: Can I marry my paternal uncle's son? His paternal grandfather and my paternal grandfather are full brothers. His father is elder to my father and is my paternal uncle. Is this marriage acceptable according to Islam?

Q: I want to know a fatwa on zina. If a girl do zina once in her life before engagement with someone else and seeks forgiveness from Allah and after sometime she got engaged with a person who did not do zina in his entire life and the girl tells her fiance that she did zina mistakenly. Now she seeks forgiveness since she did this sin. What is the order of shariah about this? Is the nikah halal or haram with that girl?