Both the sons' names are companies as well as places in Japan. Both Hitachi and
Ayako are names of Japanese royalty.
I recognize
Ayako, which makes me think it's somewhat popular. It's not bad, but I don't particularly care for the sound or meaning.
Hitachi sounds corporate to me, but no specific product comes to mind when I hear it. I don't like the sound much. Tokiwa sounds better and also more interesting to me.