Notes from research provided by my cousin's spouse, Cate O'Neal:
I have her in the 1910 OK census with her husband Samuel Schlank and son Leon R. (born 1897) living in, as you remembered, Blackwell, OK. I do know that they are in the Los Angeles city directory in 1921 living at 763 Coronado. By 1933, there is also a Rudolf Schlank at this address. Also, by that time Leon is listed with a wife Edna. The Schlank family was in OK as late as Sept 1918 because I have Leon's World War I Draft card, in which he is listed as student with the Army Training Corps in Wichita KS.