My conclusion;

Herbert H. and Philip V. Davis = Brothers
parents to above ;
Phillip H. Davis and Altha Mae Mcfarland
parents to Phillip H. Davis;
William E. Davis and ? 1910 census- mother from Illinois
parents to Altha Mae Mcfarland;
Robert E Lee. Mcfarland and Katherine J. Jett
parents to Robert E Lee;
William Mcfarland and Caroline Barnes
parents to Katherine J. Jett;
William E. Jett and Mary?

Sources of infor have been message board postings on the surnames mentioned and two Ancestry World Trees listings.
Gandolfs Genealogy Group and Rep Glen Maxey.

Although I don't have documents of my own to prove these facts I do believe the connection is there between these familys.

Surnames are found in Oklahoma,Texas,Tennesse,North Carolina,Ireland and Scotland.

Hope this helps someone else.

Keep shakin those trees!

BE