I looked at Rootsweb's California Death database http://userdb.rootsweb.com/ca/death/search.cgihttp://userdb.rootsweb.com/ca/death/search.cgi and found both Arthur and John. Arthur died in Los Angeles County, John in San Francisco County.
I know that where a parent died is not an infallible indicator of where to look for the children, but it is a clue.
It has Carol Ann, b. 1941 Los Angeles Jan Eric, b. 1943, Los Angeles Christopher John, b. 1945, Los Angeles All three entries have mother's name Butterfield.
Janice Louise, b, 1942, Los Angeles Michael Arthur, b. 1946, Los Angeles Both of these have mother's name Beatty.
The entries have exact DOB. It looks like both of your uncles married about 1939 - 1941 and spent the war years in Los Angeles.
I didn't look for the children on the death data base. I tried "Dahlstrom" in the "Surname" and both "Butterfield" and "Beatty" in the "Father's name" on the death index. Butterfield drew a blank, but there is a Kathleen Marie Dahlstrom, nee Beatty who died in 1997 in San Diego County.
All I found were more clues. Your post didn't say if you had mother's names or DOB's for the cousins. I hope I'm not just giving you clues you already have.