Those women with whom nikaah is permissible

Q: Few months back my very close friend started to like a Hindu girl (who is married to a Hindu with 1 child). Me and 1 more common friend knew about it. We advised him to move away but this girl was separated from her husband (but still in marriage) as this guy used to drink and beat her up. She is not happy rather scared of him. On our explaining, he convinced her and she had converted to Islam. We follow hanafi fiqh and as per our knowledge her previous relationship (marriage) is finished with Islam. 

Is it okay for us to do my friend's nikah with her after completion of iddah (3 periods). Is it allowed as per Islam? There is no way she wants to go back to her husband as she is already separated. Doing divorce will cost a lot in Bhutan (her own country) and she can not afford it? Please guide us if we can do nikah for him and her.

Q: I am 17 currently and I live in England. I like someone and he is 20 years old. We want to get our Nikah done as soon as possible but in the UK legal age of marriage is 18. Can I do Islamic Nikah at 17 and register it when I am 18 would it work this way?

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?