Notes I have for Samuel (II) state that his wife's name is Eva E. Census records read the same_ no clues for her NEE. Will look for ROSS as you suggested.
1910 PA Cesus Armstrong County West Franklin Twp_ Worthington__
Welton, Samuel D, age 40, married 18 yrs, Foreman @ sand plant__Eva E, age 37, 3 births 3 living children_ Viola 16, Grace 12 and Frances 6, all daughters. All members born PA
1920 PA Census_ Armstrong_Worthington Samuel 49 and Eve 46_ own the property on which they live_ there are no children at home. Youngest daughter Frances would only be 16 at this time_ circumstances unknown why she is not still living with parents.
If we continue digging thru the Ross family, sooner or later we just may bump into Betsy!