Let's see. Your message seems a little confused, but I'm going to make a guess that what you are asking is how the 'Catherine Digges' story came about. Here's what I know:
It seems that 'Catherine Digges' was first mentioned in print in the Jan 1902 issue of the Virginia Magazine of History and Biography, in an article written by a John Waterhouse Herndon.
In 1943, another Herndon, John Goodwin Herndon, apparently read the article and wrote to JW Herndon to ask him his source for the claim that William Herndon married 'Catherine Digges'.
JW Herndon replied to JG Herndon that he heard about 'Catherine Digges' from a cousin, who said she heard about it from Moncure Conway.
Moncure Conway was born in VA in 1832. He was a clergyman and a writer who campaigned extensively for the abolition of slavery. During the Civil War he moved to London. He returned to the U.S. off and on from 1884 till his death in 1907.
JW Herndon told JG Herndon that after his cousin Lucy told him that Moncure Conway told her that William Herndon had been married to 'Catherine Digges', he (JW Herndon) wrote to Moncure Conway in 1898 to ask him about it.
Sadly, Mr Conway's wife had just died and the poor man was evidently distraught, but he remembered getting some letters from some members of the Herndon family "eleven or twelve years ago when I was writing an article on Fredericksburg". So it seems that the claim that William Herndon married a 'Catherine Digges' came from unidentified Herndons who wrote to Moncure Conway around 1886-7.
However, it seems to have been John Goodwin Herndon who embroidered the claim by speculating that 'Catherine Digges' might have been a daughter of Gov. Edward Digges.
Although he acknowledges that there is no evidence for this flight of fancy, he nevertheless treats it throughout his book as if it were proven fact, so it's not too surprising that readers have assumed that he must have had proof for his assertion.
Alas, not only did he not have proof, but he seems to have completely overlooked the evidence of the settlement of Elizabeth Page Digges' estate, which shows that by 1692 all the Digges daughters were dead and only one left a living descendant. The odd thing is that Mr Herndon actually quotes from an article in the William and Mary Quarterly on Edward Digges' pedigree, published in Jan 1893, but seems not have noticed the "Addendum" to that article, published four months later in April 1893, which opens with the words:
"Further investigation shows that, when Elizabeth, wife of Elizabeth Digges, died, there were only three children, out of the thirteen mentioned on his tombstone, surviving in 1691. Only one of the dead children had a living descendant."
So that's how the myth came about, to the best of my understanding: some unidentified Herndons wrote to Moncure Conway suggesting the idea in the late 1880s; Mr Conway mentioned it to cousin Lucy; cousin Lucy mentioned it to cousin John Waterhouse Herndon; John Waterhouse Herndon put it in an article; John Goodwin Herndon read the article, and elaborated on the idea by speculating that the ghost might have been a daughter of Gov. Edward Digges.
That's how it goes. I sympathize with your frustration. I also found it frustrating when I realized I had been misled into spending a considerable amount of time looking at a family (the Diggeses) which I was not related to. An interesting family, but not mine -- and not yours either unless you descend from sons William or Dudley or from daughter Mary.
Hope this helps.