non-Muslim family members

Q: I am a converted Muslim after marriage and I really feel good that I have become a Muslim. I have also changed my name after marriage. My previous name was Nancy Nicholas and my Muslim name is Aaliyah Ali but my parents and sisters are still Christian, and they call me Nancy only. My husband doesn't like it and I cannot tell them not to call me Nancy because they will feel bad as I married so early when I was 18 and they wanted me study and do something for them. So I want to ask you:

1. My husband says, if they will call you by your previous name, you will be in gunah or crime and Allah doesn't like it.

2. Also I want to ask whether it is really important to change the name after marriage if you have a non Muslim name?

3. I heard that on the day of Qayamat everyone will be called by there names so which name I be called Nancy or Aaliyah?

Q: If an agreement is reached with the non Muslim family that the Muslims will do the ghusal, kafan and janaza namaz and thereafter hand over the body to the deceased’s non Muslim family. Will this be incorrect?

Q: If a Muslim was buried in a non-Muslim graveyard by his non-Muslims relatives, and ghusal and the Janaazah Salaah were not performed prior to the burial, can the body be exhumed for the ghusal and Janaazah Salaah to be performed? 

Q: If I am correct, it is not permissible for a woman to show/open her hair in front of non Muslim women. So if her mum and sisters are not Muslim, does the same rule apply? Also what is the rule for her to open her hair in front of her non-Muslim father and brothers?

Q: I have adopted Islam and married a Muslim man. I have two daughters from my earlier marriage who was a Hindu man. My daughters have not adopted islam yet. We keep on trying to make them understand and adopt Islam. My elder daughter is fifteen years old and younger one is 13 years old. Elder daughter gets angry whenever we talk about changing religion and wants that we should not talk to her regarding religion in future. Younger one says she will very soon adopt Islam. I want to know how should my husband interact with my elder daughter after knowing that she will never convert to Islam? I also want to know can my husband make dua for them as they are non-muslims but they are his daughters?

Q: I am a revert. Does this make me responsible for my family on the Day of Resurrection if they die as non-Muslims and am I a Dayooth if the non-believing women in my life (family members) wear whatever they want?