You didn't include any dates, or approximate dates for Rosa, so went looking at your message history and then looked at census records.Nannie always shows birth locationn for father TN and mother MO.Looks like your Nannie/Nancy and George B.
1880 census Dillon, Phelps Co, MO:
Category: Name;Relationship to head of household; Marital Status; Gender; Race; Age; Birthplace; Occupation; Father's Birthplace; Mother's Birthplace.
Alexander C. DEANSelfMMaleW40MOFarmerNCTN Sarah J. DEANWifeMFemaleW25MOKeeping HouseKYKY George B. DEANSonSMaleW13MOWorks On FarmTNMO Nancy J. DEANDauSFemaleW11MOTNMO John W. DEANSonSMaleW5MOTNMO Sophia H. DEANDauSFemaleW2MOTNMO William A. DEANSonSMaleW9MMOTNMO
Looks like Sarah J. isn't the mother of George and Nancy.Alexander is on the 1900 census still in Phelleps Co, MO, wife now listed as "Jane S." age and birth locations fit Sarah J. from 1880 census, she has had 7 ch, 6 living and they have been married 26 years, they weren't married when is first two children were born.
1870 census Phelleps Co, MO -- I wonder if the school mistress is the second wife of Alexander:
Dean, Alex C., 30, b TN - land 800/personal 900 " Susan J., 21, b MO (probably mother of first 2 chidren) " McClelland*, 3, b MO " Nancy J., 2, b MO Barnes, Sarah, 21, b MO - school mistress [*Do you suppose he was named for Gen. George McClellan of Civil War fame?Later just called George?]
Dean, John, 28, b TN - land 800/personal 150 " T____, 27, b MO " Alice J., 10, b MO
On the 1900 census, 2 pages away is an Aaron Dean, 65, b TN, NC, TN, probably brother to Alexander.If so, he is on the 1860 census "Aron" 25, b TN.I think there are 3 generations of Aaron/Aron Deans on 1860 census Phelps Co, MO.Aron 53 b NC, and Aaron 79 b NC.I do not see Alexander on that census, but being 20 he could be out on his own and missed by enumerator.I do not have access to 1850 census online, if this were my family I would check out the Aron 53 b NC on the 1850 census, I'm willing to bet he is the father of Alexander.Land and probate records should show heirs for these older men.