She is considered very attractive, and has long black hair. Calm, soft-spoken, polite, and good at cooking/cleaning (like Kasumi from Ranma 1/2). Himeko thinks of her as the ideal woman. Aiko is dating Hasekura-senpai.
Aiko's voice is done by Shiratori Yuri (白鳥由里).
Sometimes just called Yume, she is about 5 years old, excitable, nosy, and make very funny comments. Usually only seen in the Nonohara household, so she isn't hard to identify.
Yumeko's voice is done by Yokoyama Chisa (横山智佐).
Usually working busily on a book she's writing, leaving Aiko to deal with household mundanities.
Hanako's voice is done by Sasaki Yuko (佐々木優子).
He has short black hair and an unkempt mustache. Doesn't understand young girls, and wishes they'd had at least one boy. Worries that Himeko hates him (which she doesn't). Works in a film studio.