It all fits. Jane is single, age 33, in 1851, with Charles Foster. She is age 43, as Jane Boyle in 1861, with Rose Ann Foster age 11, living with them. Rose A. was 2 on the 1851. Also John Foster age 13.
Jane is 54 in 1871 with Rosanna Boyle, age 20 living with them. Same three Boyle sons as in 1861.
Jane is 66 in 1881 with Richard Boyle and same three sons.
Jane is 74 in 1891 with Richard Boyle and same three sons. Now living Campbellford, same as a possible sister Elizabeth Lennox nee Foster.
I don't find Jane and Richard in 1901. So need to look for Jane Boyle's death 1891-1901, and see if her father was Charles and someone and will likely have Elizabeth's father as well. If Jane has an obit might mention sister Elizabeth.
Now I see your death of Jarvis Boyle. Possibly related.