Is a woman allowed to travel for Hajj or Umrah without a Mahram or her husband?

I have a serious illness (Extreme dizziness) and it is difficult for me to travel or go out. Is it allowed to delegate someone to do Hajj on my behalf?

Is it permissible for a person to perform Hajj on behalf of another who is unable to perform Hajj himself because of the spread of the Corona Virus or he doesn`t meet the age requirement although he is physically and financially capable? 

If there is a man who has saved a sum of money to perform the obligatory Hajj (i.e., Hajj for the first time), and after five years he becomes entitled to enter the randomized lottery for allocating Hajj visas. In the meantime, he has a son who is single and of marriageable age. If he gets his son married, that sum could go short and so he may not be able to perform Hajj. In this case, which takes precedence? Should he do the obligatory Hajj or get his son married?

Conditions that make Hajj Mandatory ?What is the Islamic ruling on authorizing someone to perform Hajj on behalf of another

Is a Muslim obliged to sell his land in order to cover the expenses of Hajj because he has no other source of income?

What is the ruling on authorizing someone to perform Hajj on behalf of another ?