Scrooge called her "Fan" which is probably short for Fanny, a derivative of Frances.
She dies from some unanswered and questionable and in their time sickness!? "Fan" later would be referred to as "Fran"
She is never named in the original book as she is not a niece but Scrooges nephews wife
His nephew
She is never referred to be name simply as Scrooges Niece, Fred's wife of when spoken of by Fred he will use the term "Darling"
fezziwig
Ebenezer Scrooges
Fred
Fred does not have a niece
He was a trader and money lender
Scrooges house keeper
Bah, Humbug!
He was Scrooges clerk
Her name was Fan