Meaning of girl in Japanese

近頃日本の帰国子女が増えている。
The number of Japanese students returning after life abroad has been increasing as of late.

その女のこ達は、とても忙しい。
The girls are as busy as bees.

このクラスには１５人の男子と２８人の女子がいる。
This class consists of 15 boys and 28 girls.

彼女は娘の身支度を手伝った。
She aided her daughter in dressing.

私の若い娘の厚化粧は好まない。
I don't like heavy makeup on a young girl.

なるべく姉ちゃんにも周りにも迷惑をかけずに、事態の早期解決をなんとか頼むぞ。
I want you to somehow resolve the situation as promptly and avoiding to cause trouble for my sister and those around us as much as possible.

あの子はよくお使いをする。
The boy often runs errands.