Disposing of hair, nails, placenta, etc. after childbirth

Q: I have been blessed with a bay boy in January 2024, Alhumdulillah! I have with me the belly button which fell from the baby's umbilical cord after a few days when the baby was born. I also have with me his hair which I had got shaved on the 7th day. So my question is:

1. I would like to bury this belly button so called (umbilical cord) and the hair of the baby in the graveyard as I think it would remain safe in the corner of the graveyard in the mud or can I bury it in the grave of my late father? Is is permissible to do this or not? As nowadays there are flats systems so one finds it difficult to get mud everywhere.

2. My family members are saying to drown it in the river as it will be safer there and not in the graveyard. They are saying that if there is a masjid and it has a ground or yard one can get it buried there.

What is the proper way to dispose these body parts like hair, nails, placenta etc. in your opinion?

Marrying a girl after committing zina with her mother

Q: I have committed zina with my fiancé's mother mistakenly. She is my mother’s sister and I repent to Allah and ask forgiveness for my mistake. Nobody knows about this except ﷲ and us . I’m very nervous that if I do nikah with her daughter then the nikah will be valid or not and if I have children with her daughter.

I don’t understand what to do and currently it’s highly impossible to step back for marrying her daughter because if I try to step back there will be a big problem. Please bring out a solution for me. I love my fiancé very much and I can’t leave her. 

Are the splashes of water over non-flowing blood impure?

Q: If you pour water (flowing water) over a wound that is still bleeding a little when checked with tissue but the water falling off is clear (no detectable traces of blood) even though logically there would technically be blood in it, is that water and its splashes impure? Are the areas on your hand that are now wet around the wound considered impure?

Making intention for the person who purchased the qurbaani animal when slaughtering

Q: This year I gave my qurbaani money to the Muazzin and told him to give it to his family in Mozambique and purchase an animal for qurbaani. They purchased a goat.

My question is: In order for my qurbaani to be valid, is it necessary for the one slaughtering to make a niyyah to slaughter on my behalf?