Practising Deen entirely from the time one accepts Islam

Q: At the time of the Prophet (Sallallahu Alayhi Wasallam), some laws of Islam were revealed in steps, for example regarding the prohibition of alcohol. I saw that a part of a Hadith of Aisha (Radiyallahu Anha) says that "If the first thing to be revealed was: 'Do not drink alcoholic drinks.' people would have said, 'We will never leave alcoholic drinks'". My question is: is there any consideration given also to the situation of converts to Islam in our time, or do all rules of Islam become binding on them directly? For example, a woman that has lived all her life “freely” by travelling here and there, speaking to people of the other gender etc, will niqab and purda become obligatory on her the same moment she converts to Islam or will it be permissible for her to follow some more lenient rulings during a transition period, e.g. by only wearing a scarf covering the hair?

Remarrying if one finds a suitable partner

Q: I am 30 years of age and divorced with 2 kids a girl and a boy. I have been a lone parent for over 8 years now and I really feel that I need a partner and at the same time I worry for my kids too. My parents don't want to get me remarried because of the children. My mum worries too much about the kids that if their own father left them then how can a step father take care of them. I agree with her too but I am there for my children and always will be, they are my life, but there are some good people out there too. A father can leave his kids but a mother can never leave her children. Could you please tell me a dua or a wazifa that I can read so that my parents think about me and my children, accept that fact and I get a very good life partner that will accept me with my 2 kids and fulfil the duties of a real father.

Extramarital affairs

Q: My friend took khula from her husband (father of her kids) and after a year did nikaah with someone else. After 2 months she left him and went back to her ex-husband and denied her nikaah with the second husband and remarried her first husband without taking divorce from the second husband. She said that the second husband is lying about their nikaah and even filed a case of marriage jactation against the second husband in the court which is still pending. Now after 2 years she is again meeting the second husband secretly while she is still staying with her first husband and now she says that the second husband is her husband and she has sexual relationship with him and goes back home and acts like her first husband's wife and also has sexual relations with him. Please tell me who is her Islamic husband and who is doing zina with her? 

Accusing someone of of putting sihr and jadu on oneself

Q: My question is that,if you have a clear evidence that one of your close relatives is constantly doing black magic on you and your husband. Is it allowed to answer her by doing the same or what should be done to be safe from it, as there is a lot of misconceptions and fraud people doing the business. Please help as to where to go and find proper help.

Qadha of missed Qurbaani

Q: A person did not make a waajib Qurbani one year thinking that he did not own the amount of nisaab. He instead made a nafl qurbaani. After some years he realised that he had wealth put away which would have made qurbaani waajib on him. What does he do? Will the nafl qurbaani be counted for that years waajib qurbaani?