Sometimes there are coincidences. The Margaret Reardon, Sarah Norton and Hattie and Burt are different people.
I have since found that Sarah's maiden name was probably Carn(e)s.
Daniel Carns is living with the Sarah and Harvey Teeter in 1900 and 1910. In 1880 in Mishawaka, Maria Carnes 78 is living with her son Daniel 33. The next entry is for Marinda Hatfield 40 and her children Libbie 9 and Freddie 14. Then the next entry is for Sarah Thornton 38 with her children Harriet 8 and Birdie (Bert) 4. In 1850 in Mishawaka John Carns 44 and his family include Sarah and Maranda. So, Maranda Carns married a Hatfield and Maybe Sarah did also. She has Hatfield children living with her in 1870. Sarah Carn(e)s Hatfield Norton Thornton Teeter?
Just as an aside, the 1880 census for Oneida shows Sarah Norton as Single. I found an Ezra Norton with wife Margaret and daughter Sarah in 1850 in Chenango County. I think Margaret Norton remarried a Reardon when Ezra died. But, that's a different family.