The 1861 Canadian Census has a Mary Evandale, a widow, living with them....perhaps this is Lavinia's mother? Born in England and married in the year 1816 (unusual to see that info). Aged 64.
1865 NY State Census shows the family back in the US. Mary Evandale is written as Evenden in this census. Says she had 11 children. Louisa is aged 9 months on this census (so born about November 1864). Born in Kings County. In this census, it indicates that Bostick (sic) was born in Connecticut.