Update: A friend was making a trip to Ireland and brought back a postal money order for the amount I needed to send to the National Archives with my request for copies of wills. It seems that all three of my relatives left no wills. Instead, the Archives sent Administration/Probate documents that confirm George Black was the lawful nephew of James, Edward and Fanny McGinty, which answered one of my questions. Two of the documents, dated 1936 and 1938, also listed George's address as Bridge End, Donegal, and his occupation as Postman. I contacted An Post in Dublin, their heritage section, but they said they were not able to locate anyone named George Black in their records. Is it possible there would be some record in the local Post Office in Donegal Town? It is perplexing to be unable to find any trace of him after his signature on these forms from 1936 and 1938.
Suggestions are, again, welcome.
Barbara