Not related.Relatives rarely respond to this forum, but in this case there are no LANDREAUX cousins, unless you track down Andrew's siblings.
I don't know what made Andrew click, but he went from being a policeman 1900 New Orleans, to possibly being a career criminal.
1910 New Orleans, he is a prisoner in the parish jail.
WWI Draft Reg, Atlanta GA, Sept 1918 Andre Dennis LANDREAUX, prisoner US Penitentiary b 1-10-1876 Residence: New Orleans tall/med build; br eyes/dk hair Wife: Rita LANDREAUX, New Orleans
Didn't locate 1920, possibly still in prison???
1940 A D LANDREAUX 65 in State Hospital for the Insane, also there 1930; d 10-22-1942
1880 New Orleans, Orleans Parish, LA LANDREAUX N?. H. 50 LA LA LA; overseer sugar plantation Caroline 42 Switzerland Switz Switz Anthony 21 LA; M 12-18-1884 Carmelite MELLAR Maurice 11 LA Amidie 9 LA; m Pauline Andre 9 LA ******
Mrs & Miss LANDREAUX 1920 San Francisco....the info matches Rita and Ruby
Rita and Anna Ruby lived together in S F, and Ruby never married, so no desc.
Marie Rita LANDREAUX b 6-3-1874 LA: d 4-25-1954 San Fransisco; F: FERNANDEZ; M: ANDERMAN Ann Ruby LANDREAUX b 7-11-1898 LA; d 11-6-1982 Los Angeles; M: FERNANDEZ