More re Newfoundland, Seary's "Family Names of the Island of Newfoundland" has an early reference to "Nath. Smith of Greenspond, 1804". The source is the d'Alberti papers, volume 14 - transcripts of correspondance 1780-1825, between the governors of Newfoundland and the colonial office. The papers have scanned and put on-line by Memorial University of Newfoundland. Smith may be common, but Nathanial is less so - might be worth following up. Nathanial b. 1771 would have been an adult by 1804, could be the same guy.
http://collections.mun.ca/cdm4/description.php?phpReturn=browse.php&cisoroot=cns_colonia
Also, another thought about Margaret Viney - agreed that it would be unlikely for her middle name to be after her mother's first husband. Unless she was posthumous? Was there a Viney male buried less than nine months before Margaret's birth? Maybe Diana was pregnant and widowed when she married John Smith, then gave her baby both her first and second husbands' names.
Jennifer.
Could you tell me where or what page at the link above is Nathaniel Smith mentioned. The file has 381 pages.
