My wife is Japanese too, and I'm Japanese American, and one of the reasons we're moving to Oahu is just for that reason

Oahu for us seems to be the best choice, because it does have an urban, LA-like place (Honolulu), yet there are remote areas as well. Culturally, it seems like a good match for us and I don't think we'll have problems blending in.
I did a quick google search for Oahu Japanese schools (in Japanese) and came across this:
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If you can't read Japanese you'll have to ask your wife for help
Based on what's there, it does looks like there are a bunch of Japanese schools in Oahu. Looks like that site has other info as well, so we'll be looking as well
About location, we're thinking of Kapolei/Makakilo. It's a new neighborhood that's supposedly the "second city" of Oahu. It's far away from Honolulu, though and I hear traffic is kinda bad. I'm going to be telecommuting so it's less of a concern for me, but it's probably a valid concern if you need to work in town.