Questions abound. When did the story of the gunner's wife at Fort Washington first surface? Was there a direct link to the capture of Fort Washington (a letter: a journal entry)?
Presumably there are records relating to Mrs Corbin's association with the Corps of Invalids, the allocation of a pension and her death aged 48 in 1800.
As for the identification of any remains, this would require indications,, if at all likely after all this time, perhapa of the "grieveous shoulder wound"- let alone ascertaining the correct gender this time round.
(Appropriate emoticon)
With regard to records of her early life in Pennsylvania, research would be fruitless without knowing Mrs Corbin's maiden name.
I assume the nickname 'Captain Molly' was attached to Mrs Corbin at some point after the legend of 'Molly Pitcher' had become current- whether in her lifetime or in later generations. It may be worth pointing out that 'Molly' as a diminutive derives from the name Mary, as did 'Polly', while Margaret traditionally, and certainly during the C18th, has been rendered 'Meg' or 'Peggy.'