I agree that we cannot communicate with the dead.
Regarding communicating with yourself in the past, I have not completely decided if that's possible.
I rekon so too, I rekon it's demons pretending to be dead relatives to perpetuate the lies.
However, King Saul in the Bible apparently consulted a witch or medium to speak to the dead prophet, Saul.
Now weather this was the case, or what spoke to Saul was a demon or the fact that this was before Christ's resurection makes me wander, as it does say he spoke to him.
Any thoughts?