Hair and Nails

Q: Is it permissible to remove facial hair (except eyebrow hair) that are on the sides of face under the sideburn?

Q: Can you please tell if I can put black mehndi on my hair? Is it not allowed in Islam?

Q: Can one clip nails at night?

Q: I would like to know if the unwanted hair of the human body is napak. If one shaves the private parts and the hair which has come out is considered napak or not.

Q: From which age is it mandatory for a boy to shave hairs around the penis or lower body?

Q: Can a male or female tint his/her hair black or any other colour, if their hair is black? 

Q: Is it allowed to pluck the extra hairs on the eyebrows if a woman has broad and irregular eyebrows. She is not doing it to keep thin the eyebrows. It is only to look good for her husband.

Q: As a female, would it be haraam for me to cut males hair into different styles like how a barber would?

Q: I would like to know if you are allowed to shave your hair on your backside and anal region. If not, which places are compulsory to be shaven?

Q:

1. Is it haraam or makrooh to cut the hair in different lengths?

2. If I want to cut my hair short on the sides and keep it long on the top, but my intention isn't to imitate anyone and I'm only doing it because I believe I would personally look better, would this be considered haram?