Sharp wrote 'Some Conclusions' based on his collecting experiences. He published many anthologies BUT has anyone seen ANY evidence that would suggest that he was a folksong scholar regarding their history and texts?

Do we know, for instance, how big a collection of broadsides he had in his possession (which we do in the case of Baring-Gould)?

I'm not quite sure what you're looking for here, Steve, but if it's any help I found the following in Sharp's correspondence from North America:

“They ][mountain people] are wonderful singers and fond of singing and of their own songs and sing far fewer of the 19th century broadside versions of the words than do the English peasants.”

To a 'Miss Smyth' regarding claims that most folk songs had originated in Ireland:
"Stopford Brooke says that the English language was not used for particular purposes in Ireland prior to 1790. All of the Irish folk songs to English words are, therefore, subsequent to that date. As a matter of fact, what really happened was that the Irish ballad-printers copied freely from the ballad-broadsheets issued by Pitts, Evans, Such, Catnach and other English printers. I have a very fine collection of Irish broad-sides, which make this quite clear."

And this to his wife:
“By the way when you get back home and you have some time to spare will you copy out the words of my broadside called ‘Nancy of Yarmouth’. It is in my very first vol. of broadsides – the one you indexed for me… I wanted to compare it with certain songs I am getting here.”