Perhaps it would be helpful to show the approximate ages you are looking for.

1900 US Census: Blackwell Township Blackwell city Ward 1-4, Kay, Oklahoma Territory, pg 15
Albert Downing M Oct 1873 26 married 3 yrs Kansas Wisconsin Indiana Day laborer
Cora Downing F Sep 1879 20 married 3 yrs mother of 1/1 living Kansas Wisconsin Kansas
Francis I Downing F Mar 1899 1 Oklahoma Kansas Kansas

I would not count on the accuracy of the grandparents birthplaces. I didnt find them in 1910.