hair extensions

Q: Are fake lashes and fake nails allowed or not, like fake hair extension (wig)?

Q: If the deceased has nail polish on their nails, should the person giving the ghusal remove the nail polish? Similarly, if the deceased has hair extensions (human or non-human) attached to their hair, should the person giving the ghusal remove them?

Q: Is it permissible for a woman to put extensions on her hair?

Q: Is it permissible to sell wigs?

Q: According to one of your answers on this site about wigs and hair extensions, you said it is permissible to wear provided the hair is synthetic (not made from human hair), but I came across these hadiths regarding this that I want you to elaborate on please:‎

Asmaa' bint Abi Bakr said: "A woman came to the Prophet (Sallallahu Alayhi Wasallam) and said, 'O Messenger of Allah, I have a daughter who is going to be married; she had a fever and lost much of her hair - can I give attach false hair to her head?' He said: 'Allah has cursed the one who attaches false hair and the one who has this done.'"(Reported by Muslim, 3/1676).

Jaabir ibn 'Abdullaah said: "The Prophet (Sallallahu Alayhi Wasallam) issued strict instructions that no woman should add anything to her head." (Reported by Muslim, 3/1679).

Please kindly give proof from your own replies and may Allah reward you immensely for this great work.‎