I happen to know this family, if its the same people you are looking for.Manuel Jr. and Marilyn went to Lincoln High School together, and Margaret (his mother I believe) lived on Sichel St., in Lincoln Heights.
I grew up with Manuel Jr. and Marilyns children.The children are: Manuel Allen III b. 07-1959 Melody Ann b. 10-1960 Melissa b. 09-1963
You have Marilyn's maiden name incorrect, but it does sound close to the Davies surname you listed.