First you have to check if the voices are oké with this range: Norah Jones' voice goes very deep (to the Eb below the central C).
It is not possible to play all the sung notes on the piano, because the song is very recitative. That makes it more difficult for the singers: there is no clear beat in the song to follow. (For the same reason it could be possible that it is difficult to sing together. Perhaps the singers could sing solo, alternately)