Hi Cyrus, I thought I had a record of John W. Stell in the 1860, but I can't find it! I will tell you what I do know.
1860 As you mentioned the mother Elizabeth is living with Jesse D. Kennedy and daughter Martha E. Stell KENNEDY and Elvira is living with her sister Elizabeth L. STELL KENNEDY. Ann married a E. K. B. PATTERSON. I don't have a copy of them in the 1860 census, but I do have the 1870.
1860 Cherokee TX pg. 163 #1077 KENNEDY Jesse D. 35 Missouri " Martha E. 31 KY " Susan 1 TX STELL Elizabeth 59 SC
1860 Cherokee TX pg. 450B #532 KENNEDY Alfred 39 ILL " Elizabeth L. 28 TN " Wm. J. 6 TX " Jno. A 4 TX " McClain 1 TX STELL Elvira 14 TN
1870 - Martha is remarried for the third time to a William J. LOFTIS. Mother Elizabeth still lives with her. Alfred Kennedy has remarried, because Elizabeth L. has died and Alfred moved his family to Johnson, TX. I have not been able to find Elvira STELL in the 1870 or evidence of a marriage record for her. I have however found a widowed Mary PARKS STELL in 1870 DeWitt TX.
1870 Cherokee TX Pg.295B #283 LOFTIS, William J. 25 ALA " Martha E. 38 KY " John W. 10/12 TX KENEDY Susan 10 TX " James 8 TX STILL Elizabeth 68 KY
1870 Cherokee TX PATTERSON Elzy. K. B. 34 GA " Ann E. 32 TN " Amanda E. 10 TX " Elizabeth 8 TX " James A. 4 TX " Martha C 8/12 TX MACK Gus 26 TN
1870 DeWitt TX STELL Mary J. 33 ARK " Josephine 16 TX " Sarah Ann 14 TX " John E. 13 TX " Cyrus H. 10 TX
Elizabeth STELL (mother) died and is buried in Cherokee county. I thought I had the record for John W. STELL in 1860, but I can't find it. I will let you know when I do.