Those women with whom nikaah is not permissible

Nikaah with a woman who is still in her first husband's nikaah

Q: I recently got married but we are now finding out that the girl did not get talaq from her first husband and the girl relied on a civil divorce to constitute the talaaq. 

The first husband of this girl says he didn't institute talaaq and the civil divorce was only for the courts. 

The second nikah has taken place before we found out. Is it valid?

Marrying one's foster aunt

Q: There's a girl and we like each other. Finally we decided to get married. 

The question is, she's a sister of my aunty (chachi) (my father's brother wife) and my aunty (chachi) is my foster mother as she fed me breast milk two times only while I was 18 months old. 

So am I allowed to get married to her sister or not?

Marrying a Shia

Q: I am 27 years old, financially independent, interested in a girl and want to get married. My parents disagree because she is a Shia and I am a Sunni. I have tried to convince them a lot, get elders involved but they don't listen. The girl I want to marry perfectly matches the criteria of my parents even the caste but they have reservations over the sect. The main issue is what will the family or people say and we will be a joke that we married you to a Shia girl. They have said it multiple times that socially we can't face people and hence we won't marry you. I am forcing them on it and they said they won't be a part of it but will give duas and stuff but can't be a part of it. I want my parents to be happily involved in it but they want to marry me of to their choice especially my mother. They say parents have a right. Please tell me what to do and what is the Islamic ruling on it.

Marrying one's step brother's daughter

Q: I have a step brother (same father, different mother), one of his daughters have been recently widowed. I myself am divorced recently as well. A few people have raised a question about us getting married since my widowed niece is just half niece.

I am clear on the ruling based on Quran (Chapter 4, Ayat 23) that this not allowed.

Can I please request guidance on this please?

Marrying a Shia

Q: I am a sunni girl, Sayyed by cast and got a proposal from a Khoja Shia non Sayyed boy.

My question is, is it ok to get married into a Shia family? If so, what is the right way to do nikaah? Should it be done both ways? 

Marrying two sisters

Q: My husband manipulated my sister and got married to my sister without giving me a divorce. When my sister got to know that their marriage is not valid after a year, she got married to another man. That man left my sister beacuse he thought she did nikah on nikah, but that was not the case.

Wishing for one's non-Muslim girlfriend to accept Islam

Q: There is a Hindu girl that I like and I wish to marry her in the future (we both are 16 years old) as I don't want to have any haraam relationship with her. Is there anything I can do to inspire her to embrace Islam with her heart, mind and soul so I can marry her?

I genuinely care for her and I don't want her to go to hell because she is a very good, generous and honest girl. Please guide me in this matter. I can take things slow and cautiously with her if I can inspire her to embrace Islam.