Hi,
Interesting post, I'm a Takaki who's parents lived in Diamond Bar. It would be hard to imagine that there are more than one. I had 2 brothers that were born a year before and after that birth date. I never heard of them having any kids that were given up for adoption, but then again people don't usually speak of things like that.
There was one child named Dewan, Dewahn or Diwahn Cole (Takaki), birth year about 1985?, not sure of spelling and I know that his grandmother cared for him. His mother is Deborah Ann Cole (African American), father Kiyoto Takaki aka Harry