Just found reference to this family in Welland District (Fort Erie?) . Letitia may be sister to my G-Grandma Elizabeth (McVittie) MacTavish. MacTavish family came to Canada in 1907, settled in Fort Erie.
From the 1911 census:
Archibald b 1878
Letitia b 1885
Sarah b 1905
Neil b. 1911
Archibald may have died in 1911. Letitia was pregnant but the child, Agnes b. July 1912 died in September 1912.
Letitia's surname, McVittie, noted on Agnes' death cert.