Amazing story, Don.
I believe that NDEs are the most valid way of getting a look at the other side.
Your idea about the two mediums is of high merit. But as it is all second hand, and some mediums like Edwards don't actually have conversations, but see flashed of images or pictures, I'm not sure that you could easily ask the medium to have your dead mom chat with your dead dad, etc.
I also believe, as I've said before that based on Swedenborg's experience, specific information is likely only to be quickly supplied by the very recently deceased.
I believe that few mediums will subject themselves to controlled experimentation. Edwards and a few others have allowed it, but most mediums are not interested in doing so.
A great idea however.
I also like the idea of cross correspondences to test mediums proposed by Frederic Meyers. This occurs when several different mediums receive pieces of a message which independently mean nothing, but when assembled together yield a coherent message. It was said that Meyers planned to send different messages, and after death many mediums began to receive strange messages that on their own did not make sense:
http://www.victorzammit.com/book/chapter16.htmlI haven't investigated these thoroughly, but it seems that if one could plan, prior to physical death to devise a message and send it through to different mediums in pieces like this, there would be strong evidence that a deceased person was in fact transmitting messages.
Matthew