In her initial appearances, Okano was often shown to be serious with a relatively neutral expression. As the series goes on, she's later shown to also be playful in addition to being serious.
Okano (岡野) Oka (岡) means "hill" or "rising ground" and No(野) means "field." "Okano" is also the surname of one of the 47 ronin of feudal Japan.
Hinata (ひなた) is a unisex name meaning "sunflower" or "facing the sun."