Too many, but not enough. Will* Jackson is a very common name

No likely looking Willie/Will/William Jacksons in California Deaath records ....several died in CAL but birth states & mother's maiden name were not likely.

This one was in Ancestry's WWII enlistment records.

Name: Willie J Jackson
Birth Year: 1916
Race: Negro, citizen
Nativity State or Country: Mississippi
State: Missouri
County or City: St Louis City

Enlistment Date: 18 Sep 1943
Enlistment State: Missouri
Enlistment City: Jefferson Barracks
Branch: No branch assignment
Branch Code: No branch assignment
Grade: Private
Grade Code: Private
Term of Enlistment: Enlistment for the duration of the War or other emergency, plus six months, subject to the discretion of the President or otherwise according to law
Component: Selectees (Enlisted Men)
Source: Civil Life

Education: 1 year of high school
Marital Status: Married
Height: 00
Weight: 000

Have you tried St Lousi city directories from the 40's or 50's for these people? Might get a wife's name.