Masaail pertaining to the Wali and Compatibility between spouses

Q: Is marriage of a Sunni (Deobandi) girl valid to a Shia boy?

Q: I love a girl and she is a Wahabi girl and I am Ahl e Sunnat. Is it permissible in Islam for me to marry her?

Q: I am a 17 year old high school student, and really embarassed to ask such a question, so I seek Allah's forgiveness.

Since few months I have developed feelings for a celebrity girl who is in my age group. Though the intentions are not ill but I really want to marry her and oftenly ask Allah to make me marry her.

Is this type of dua ok and what should I do about it? Can you please guide me as per Islam.

Q: I am about to turn 19 and live in Canada. I am baligh since the age of 9 (which means I had my periods). I am currently in college and I like a guy. I want to do nikkah but my parents don't allow nikkah at such a young age specially till I don't complete my studies which has around 5 to 7 years.

I am scared of doing something haram (like zina) and I want to turn it halal as soon as possible. I have the witnesses, I am completely sure about this marriage since the guy belongs to a good family which is also religious and fulfils its Islamic duties. But I recently heard that nikkah without the consent of wali is invalid.

Now my question is, in what Hadith or verse of the Quran is it mentioned that the father should be wali? Can I make an imam my wali? Or can I conduct my nikkah without a wali while fulfilling other conditions such as witnesses, and haq mehar.

A detailed response over this matter for better insight would be appreciated. 

Q: Can a Muslim man make nikah with a second wife who is a Christian woman and then go to the church and watch her being baptised. Is this kind of marriage valid and accepted in Islam?

Q: I want to marry a woman who has become Muslim, but her family is kafir. Her father is divorced from her mother and has not lived with him for more than 10 years and she lives with her mother and younger brother.

In this case does the girl need to ask permission or have the consent of someone from her family (Wali) or can she marry me only with her own consent?

Q:

1. My husband married a Christiam girl who didn't convert to Islam. Is the nikaah valid?

2. He stays 1 night only with us and its affecting my children now. Is this permissible? He treats me, as a first wife, very badly. He talks rudely to me and is always angry with me. His 2nd family is always treated well.

Q: I'm a taalibul 'ilm (studying Dars-e-Nizaami). I have no objections with what is said, but I'd merely like a clarification and an explanation if possible.

I came across the following question on Muftionline: https://muftionline.co.za/node/33372

At the bottom, as a note, Hadhrat mentions, "The above ruling applies to the case where the boy and girl are both non-Arabs and both their parents and grandparents are born Muslims (i.e. they are not converts)."

Q: Can a Muslim woman marry a Muslim man of another caste or ethnicity/nationality where there are differences in cultures and thoughts.

Q: I'm a Muslim and my husband left Islam a year ago and became an Athiest. Since then I am living seperately from him and tried my best to bring him back for the sake of our kid. Now he wants to become a Muslim again. I want advice on what should I do in terms of Islamic law since our marriage was over when he became an Athiest. I want to reconcile as well. But whats the procedure for me and also for him to return back to Islam?