Factors that make Zakaat compulsory

Wealthy Muslims taking loans from the bank

Q: In our time, there are wealthy Muslims to take out loans from the bank for tens of millions of rands for the purpose of business, e.g. constructing an apartment block. Or taking out a mortgage for buying a home. Please advise:

(1) If the amount loaned exceeds their Zakaat asset value, does that mean these Muslims do not have to pay Zakaat, and that they are also eligible to receive Zakaat?

(2) Likewise, is it better for them to use money to pay off debts or Nafl Sadaqah/Lillah projects?

Obligation of zakaat and qurbaani if one has a share in a property

Q: My father passed away in 2021 and, we, the heirs (mother, and 3 brothers, all adults) inherited property and cash as per shariah.

1.The cash was given by us to our mother. We made her the owner of that cash.

2. The property inherited (2 x 5 marla plots) are combined property of our mother and 3 brothers, the net worth of shares is above the nisaab.

Our mother pays yearly zakat as well as Qurbaani.

The question, Is it compulsory for us 3 brothers to pay zakat and qurbaani, provided that our indiviual monthly incomes/savings are less than the amount of nisaab (cannot even buy or share an animal for sacrifice and neither of us can move/sell, the shares of property, or use for any business means). Will zakat and Qurbani be applicable on this sort of shared property?