Also have found information that links Thomas Davis, Henry Davis and Samuel B.B. Davis to similar units in the 4th Tennesse Calvary:

The following is a listing of all the Davis's listed in 
Starnes'-McLemore's regiment:
Henry J. Davis APrivate
John R. Davis BCaptain
N. C. Davis DPrivate
Samuel B. B. Davis KPrivate
Scott D. Davis APrivate
Thomas Davis KPrivate
William Davis FPrivate
William Davis IPrivate
William H. Davis BPrivate
William K. Davis F&SAdjutant
William R. Davis KPrivate

Samuel B. B. Davis definitely is related. I suspect that Thomas Davis and Henry Davis are most like related too but no definite tie in.  Not sure what Thomas' middle name was.  I will need to try and secure the compiled service records for same to confirm.  If anyone has this let me know at randyddavis@hotmail.com