What should these Muslim-owned banks do to make their dealings Shariah-compliant?

Answer

They only have to institute some simple changes. If the Muslim-owned banks discard interest, and if they fumigate their brains to eliminate pegging the Shariah with the capitalist system thereby making Islam subservient to the kufr riba system of the capitalist world, their system will become automatically Shariah-compliant. The Islamic system is simply not to charge interest. They should discard also their deception of promoting their business dealings as muraabahah, mudhaarabah, mushaarak, etc.