Hi Regis. You might want to add Spain to those tags. I looked on the Hawaii site and didn't see the last names Guardia or Munoz in passports, denization or naturalization. Did either of them marry there? I see you have already tried the FamilySearch site, but you may want to try again taking out birth date estimates, etc to see if something new pops up. I wish I had been more help!
I do see a passenger list for Francisco from Hawaii to California:
"California, Passenger and Crew Lists, 1882-1959," database with images, ''Ancestry'' ([https://www.ancestry.com/interactive/7949/CAM1410_169-0412?pid=472236 Passenger Lists] : accessed 7 July 2018), entry for Francisco Dominguez, 8 Mar 1923; citing Selected Passenger and Crew Lists and Manifests. National Archives, Washington, D.C. TEXT: Name: Francisco Dominguez, Gender: Male, Birth Date: abt 1873, Birth Place: Spn, Age: 50, Arrival date: 8 Mar 1923, Port of Arrival: San Francisco, California, Ship Name: President Wilson, Port of Departure: Honolulu, Hawaii, Destination: San Francisco, California, USA, Last Residence: USA, Accompanied by: Lorenzo, Friend's Name: Lorenzo Dominguez