Is it permissible to mortgage a commodity, as a security for funding, prior to concluding the Murabaha or Istisna` contract, knowing that an initial funding contract had been signed?

If one person sold his car to another by installments, and the latter sold the same car to another through the same manner, but the second person asked the third to mortgage the car to the first one; does the first seller have the right to collect the installments of the debt owed to him by selling the mortgaged car ?

Is  purchasing a flat via Murabah contract from the  Arab Islamic Bank and mortgaging it to the latter lawful or unlawful from the view point of Sharia?

A certain company wants to get a loan from a certain bank, but the latter stipulates that the former mortgage a property in its favor. Since the company has no property, a friend volunteered to mortgage his property as collateral. Is it permissible for the friend to receive an amount of money in exchange for that?