Today, I found the original of Edmund's will. What a relief.
It was in one of a series of higgledy-piggledy files containing some fifty years' worth of family letters, a mother lode of old playbills, and far too many Certificates Suitable for Framing, in a tape-sealed brown envelope that had been stuffed into a folder of faxes and Xeroxes from the Canadian Forces Release Centre. I'm surprised/not surprised that it took me so long to find it, but of course it was beautifully camouflaged, in the filing cabinet along with all its buddies.
The lawyer was very happy -- nay! thrilled to bits -- to see it. Suddenly, the task of getting Edmund's estate through probate is a whole lot easier.