I think that Benner must have been a previous married name. Stella has her mother, (Nancy) "Mary" J. (Graham) Bell living with her in 1940 just before Mary's death.

Mary J Bell in the 1940 United States Federal Census (April 22, 1940) (a few months before her death)

Name: Mary J Bell
Age: 84
Estimated birth year: abt 1856
Gender: Female
Race: White
Birthplace: Indiana
Marital Status: Widowed
Relation to Head of House: Mother-in-law
Home in 1940: Everett, Snohomish, Washington
Map of Home in 1940: View Map
Street: Lumbard Street
House Number: 3015
Inferred Residence in 1935: Rural, Lebety, Texas
Residence in 1935: Rural, Lebety, Texas
Resident on farm in 1935: No
Sheet Number: 3B
Number of Household in Order of Visitation: 102
Value of Home or Monthly Rental if Rented: Cont
Attended School or College: No
Highest Grade Completed: Elementary school, 8th grade
Weeks Worked in 1939: 0
Income: 0
Income Other Sources: Yes
Neighbors: View others on page
Household Members:
Name Age
A C Welch 68
Stolla C Welch 62
Mary J Bell 84

Stolla above was born in Kansas. I am sure it is Stella since she has her mother in the household. I am sure that Lebety Texas is Liberty.

I am finding it odd that her memorial has her married to A C Welch when her death records list her as (Bell) Benner.

Stella C Benner

in the U.S., Social Security Applications and Claims Index, 1936-2007
U.S., Social Security Applications and Claims Index, 1936-2007 No Image
Text-only collection

Name: Stella C Benner
[Stella C Bell]
SSN: 532589147
Gender: Female
Birth Date: 28 Sep 1877
Death Date: 1 Dec 1968
Father: Bell
Claim Date: 13 Dec 1968
Type of Claim: Death Claim
Notes: 11 Dec 1968: Name listed as STELLA C BENNER

Stella C Benner in the Washington, Death Index, 1940

Name: Stella C Benner
Gender: Female
Residence Place: Everett, Washington, USA
Death Date: 1 Dec 1968
Death Place: Everett, Washington, USA
Certificate Number: 029275