Is it permissible for the buyer to pay the expenses of the initial contract (between the bank and the property owner), and does the buyer's dwelling in the property before the completion of the Murabaha contract affect the validity of the contract?

Firstly: The expenses of the initial contract are borne by the seller or the bank. If the bank pays them, it is permissible to include them in the Murabaha, because Murabaha is a sale at the initial price with an added profit. The price includes expenses related to the commodity that are customarily added, because expenses paid to a third party are appended to the price, and there is no usury in that.

Secondly: The buyer's payment of expenses that are incumbent upon the bank is considered a gift for the purpose of the sale and to avoid adding Murabaha profit. This is prohibited by some scholars due to the Prophet's (peace be upon him) prohibition of combining a loan and a sale; combining a compensatory contract and a gratuitous one for the sake of the compensatory contract makes the gratuitous act part of the consideration. Therefore, one should not interfere in the transaction until the bank purchases the property and then sells it.

Thirdly: There is no objection to the buyer residing in the property before purchasing it from the bank, whether the residence is free of charge or for a rent. This does not affect the Murabaha, unless the buyer purchases the property from its owner, even without paying a price, as this invalidates the Murabaha with the bank and makes the financing a trick to engage in usury.