How would you "translate" a scene from Death of a Salesman into visual/aural expressions on the stage? Who would you cast for the characters and why? What kind of sets, costumes, lighting, sound, and music would you use and why? How would your analysis/design maximize the potential of the play on the stage and help the audience fully understand and enjoy the production?

If you were to use the scene in Act II in which Willy Loman talks to Howard about Dave Singleman, Willy's ideal of the successful salesman and the man he hoped to be like, it might be best to have Willy step away from Howard and into a dreamlike setting. Remember that these are merely suggestions to prompt your own thinking. Perhaps fog or smoke could represent that Willy has entered fantasyland, while the part of the stage with Howard grows darker. I might use some sort of dreamy music (you might try to think of a specific piece), have the sound coming as if from far away, and perhaps put a strong spotlight on Singleman. Since Willy thinks of Singleman as representing easy money, it might make sense to have him lolling about in an almost exaggerated way: maybe his green velvet slippers could be a very bright green and oversized and his chair very plush as he makes big deals just talking on the phone. Think about ways you could exaggerate Singleman to show how Willy has built up an exaggerated image of him.
As for who should play Singleman, you would have to use your imagination, but I picture a person like James Gandolfini, who played Tony Soprano, or Jack Black.
All of this would be meant to help the audience understand how much Willy has built Dave and the idea of easy money into an oversized fantasy.
Again, these are all merely suggestions, and you will need to apply your ideas and imagination to fleshing this out more fully. Best of luck with this!