I am part of that family. It turns out that Aaron was not born in Wales but in Pennsylvania. In the 1850 census he was age 54, listed as a farmer in Muscatine, Iowa. That would have made his birth date as 1796.
Your g-g-grandfather, Joseph Morrison Davis, was born in Stark Count (not Stork), Ohio, September 14, 1833.
I, like you, have loads of information on Aaron P.'s children. Have his wedding date . . . and approximate birthdate of Ruth Edwards, his wife. Have also located a brother of Aarons, Charles Samuel Davis, born in 1848, also in Ohio.
I can be most easily reached at:firstname.lastname@example.org
I am the editor/publisher of a weekly newspaper in North San Diego County. Born in Minnesota but grew up in Omaha and know the Blair/Herman/Tekemah area quite well.
Look forward to hearing from you.