I don't think there is a connection in my husband's family with Bennie Wallen, if the one you are looking for was born in 1928,( I found him on the social security death index) but I am not positive. I asked by husband if he knew of any Bennie in the family, and he told me he did not know of one.
There is a Lillie Leona Wallen, who was a sister to my husband's grandfather, who was born 9-6-1874, married 8-1889 in Chicago, and died 9-7-1962 in New York.
Have you checked Nebraska or Californiacensus records for 1930?
My husband's dad was one of 8 children. There names are:Harold, Raymond, Chester, Lloyd, Lois, Bernice, Edna, Mary Ellen. Lois ( which is a similar name to Lena) had 3 children, 2 girls and a boy. The boy's name was Gary, though. I don't think that she had any other children, but again I am not positive.
I ran across a young girl about 8-10 years ago, who lived in Baldwin Park, CA., whose last name was Wallen. We briefly talked about our families, to see if we were from the same Wallen line, but we were not. Her father and an uncle were living in Baldwin Park at that time.That might be a connection for you to try to follow up on.
If I come across any other information that may be of help to you, I will let you know. I wish you all the best with your search--I know you will eventually find your family.