BTTM Census Search: Emily Mitchell (1840-1892)

Married to Matthew Daniel Savage on 10 Aug 1856 in Rigby, ID

Need to locate her in:

1860 US Census: Children born in Salt Lake City, UT around that time
1870 US Census: Children born in Wanship, Summit, UT before (1867), and Willard, Box Elder, UT after (1874)
1880 US Census: Found family in Willard, Box Elder, UT

BTTM Census Search: Mary Jane Savage (1860-1957)

Need to determine her married name.

Cannot find her as Savage on any Census. Need to do detailed search from home on the following:

1860 US Census: Cannot locate her parents.
1870 US Census: Family found, she's not listed (age 10).
1880 US Census: Cannot locate her as Savage.
1900 US Census: Cannot locate her as Savage.
1910 US Census: Cannot locate her as Savage.
1920 US Census: Cannot locate her as Savage.
1930 US Census: Cannot locate her as Savage.

Born in Salt Lake City, UT.

Obituary? -- she lived to be 97 years old.

Note: She has a twin(?) sister named Sarah Jane Savage -- could this be the same person, instead of twins?