I tell you the truth, a time is coming and has now come when the dead will hear the voice of the Son of God and those who hear will live.
It`s an interesting point you make, but I don`t think it`s meant to be taken symbolically, like you think. The JWs just ignore this verse, or believes it refers to the dead after they have been risen, but as you correctly point out, they hear this while still dead! The "dead" here means those who have (physically) passed away. There is nothing symbolical about it. In jewish thought and belief at this time, the souls (or what would then be called "spirit") of the dead did not cease to exist after the body had died. It went either to Sheol (the underworld) or to heaven (to the "bosom of Abraham").