"How do we compellingly demonstrate that moral language (that is, our use of words like 'good,' 'bad,' 'right,' 'wrong,' 'should,' and 'ought') can be cashed out entirely in non-moral terms (e.g., in terms of expected and realized value of actions) with nothing important left over?"

Why not conduct an experiment and stop using 'moral language' for a week and see if you hit upon something that is inexpressible without it?