Jahannum;non muslims questioning in the grave;beard;hair colour

Assalamualikum Mufti sahab hope inshaAllah you and your family doing good.

Q1. Who will be the first person to be free from hell?

Q2. When non Muslims die will he or she will be asked questions of grave or straight away they will be punished?

Q3. Can a Muslim make his beard hair straight by using creams or machines? is it permissible in Islam to go against nature?

Q4. Can Muslims use other hair colour except black?