No definite proof, but the birth of son Glen shows his full name as Wenceslao Glen Loaiza, so likely named after his father. And mother's maiden name was Metsker
Also, son Stephen's middle name was Morell so another connection.
California Birth Index, 1905-1995 about Wenceslao Glen Loaiza Name: Wenceslao Glen Loaiza Birth Date: 26 Jul 1943 Gender: Male Mother's Maiden Name: Metsker Birth County: San Joaquin
California Birth Index, 1905-1995 about Stephen Morell Loaiza Name: Stephen Morell Loaiza Birth Date: 19 Dec 1941 Gender: Male Mother's Maiden Name: Metsker Birth County: San Francisco
California Birth Index, 1905-1995 about Shannon Katharyn Loaiza Name: Shannon Katharyn Loaiza Birth Date: 1 Jul 1940 Gender: Female Mother's Maiden Name: Metsker Birth County: San Francisco
ALSO California death index for Wenceslao who died in 1943 shows his parents names as Morell and Loaiza which seem to be another confirmation you have the right fellow.
California, Death Index, 1940-1997 about Wenceslao Francisco Loaiza Name: Wenceslao Francisco Loaiza Social Security #: 556070167 Gender: Male Birth Date: 6 Apr 1911 Birth Place: California Death Date: 19 Mar 1943 Death Place: San Joaquin Mother's Maiden Name: Morell Father's Surname: Loaiza
I cannot find any other W.F. or Wenceslao Loaiza men in census and along with the rest of the info I do believe that this is your fellow BUT a marriage record would help to prove it for sure. The California marriage index starts in 1960 though so no luck there.
If you email me at firstname.lastname@example.orgI can also give you some marriage and directory info I found for some Loaiza folks who may be related to yours - it does look as though Katharyn and children likely went to Oregon after death of Wenceslao.