What is the opinion of Sheikhs Ibn Baz and Al-Othaimin regarding purchasing homes and cars through Islamic banks, knowing that most banks do not physically possess the asset but merely transfer ownership?

Murabaha to the one who promises to purchase is permissible if the bank adheres to the Shariah guidelines. These include the commodity entering the bank's ownership and its possession, whether actual (true) or constructive. Constructive possession is sufficient for considering the acquisition and ownership, and its meaning is enablement, clearance, and the removal of impediments customarily and ordinarily in reality. This is supported by the Prophet's (peace be upon him) sale of a camel to Umar, and then his gifting it to Ibn Umar, where ownership of the camel transferred immediately upon the contract without actual physical possession. The transfer of ownership to the bank and the commodity entering its liability is considered constructive possession, upon which Shariah effects are based.