Funerals of non-Muslims

Q: My wife is a converted Muslim and her father has recently died who was a Hindu. There are some rituals that only my wife can perform as she is the only child. I am not sure wether to allow her to perform that rituals which may involve a Puja as well. Can you please guide me what happen if she still perform such rituals despite knowing that I am not happy if she performs those.

Q: Is it permissible for a Muslim to attend a thanksgiving service for the deceased person at a church?

Q: A certain persons granny is non muslim and is on her death bed. She would like to know:

1. Can she and her family attend the funreal / service if it is held at a church?
2. Can they attend the function held after the burial which would be at a church? (From what I understand it is a meal with the family)
3. Can her mum accept and use inheritance from her non muslim mum?
4. Also a muslim sister says that she has reseacrhed that niqaab is not fardh for hanafis. Could I please have some information proving that it is fardh?

Q: Is it correct to write R.I.P (may he rest in peace) for a non-Muslim after his demise? What does Islam say about this?

Q: Can I assist with / attend my uncle's funeral (non muslim) in the month of Ramaadan? The funeral is on Saturday (27 July) and I would like to help my aunty at her house and in the hall (serving tea, etc)?

Q: Is it allowed in Islam to attend funerals of non Muslim and go into churches for funeral ceremonies. Please put some light on this.

Q: Is it permissible for a Muslim to attend the funeral of a non-Muslim?