Daisy,
I know I'm a bit late to this thread, but I might have some information relevant to your earlier queries:
1. Was she a convict?
2. Who were her parents.
3. When did she arrive? What was the name of the ship and what is a good website to get this info?
4. Did she have any siblings?
5. Did she ever marry? I don't think she did because she was referred to as "Mrs Emmett" in her death notice (trove.com). 1899
6. What happened to her after E.N. Emmett left her? I have found one reference to Jane Dolby lining up for destitute relief, having three children by Emmett. But that is Jane, not Sarah.
7. Was her father or mother a convict.
I'm a descendant of Henry James Emmett (who arrived a free settler in Hobart Town in 1819), father of Edward Nucella Emmett. I don't have much historical information about the Emmett side of my family, BUT I'm currently editing a manuscript written by my Grandfather (E T Emmett) but not published before he died.
I would describe the book as an historical novel, in that it is based on the lives of the Emmetts after their arrival in Hobart, but Grandad has changed the names of family members to protect their privacy (even though they're all now deceased!).
However there are two chapters that deal with a romance between one of the Emmett boys and the daughter of a convict, and we believe that boy to be Edward Nucella Emmett. Given the dates this romance occurred around, I also believe the girl to be Sarah Ann Dolby.
Because Grandad changed all the names, I can't be sure, but the dates fit. If you want to PM me your e-mail address I could send you a few chapters of the draft book that deal with Edward and Sarah (named James and Rebecca in the book), and her father, known as Mr Grieve in the book, who was assigned to Henry James Emmett as a servant. He was not a bad man, but ended up an 'accidental convict' because of unfortunate circumstances. But he did some good for my ancestors, if Grandad's book is to be believed (it's supposedly based on the letters and journals of his ancestors), and was subsequently granted his freedom and was then able to bring his wife and children out from the UK, one presumably being Sarah.
Wikipedia has a page about Edward Nucella Emmett which mentions his (de facto) relationship with Sarah. (My grandfather, E T Emmett, also has a Wikipedia page.)
Daniel