The kanji characters for Keine translate loosely to "Wise sound" while Kamishirasawa literally means "Upper stream of a white valley." However, the Kamishirasawa kanji can be read as "ue hakutaku" or "uwa-hakutaku" and so likely a pun by ZUN when he named the "Were-Hakutaku" character.
"Keine" is also a declensional form of the German word of negative article or negative determiner as "no" in "No one shall sleep tonight". Although the two words are pronounced differently, Keine's name used in this manner may also be a reference to her ability to negate history.
Most of her spell cards are based on the history of the Emperor of Japan.
Keine seems to have a strong desire to protect humans and would probably be the safest person in Gensokyo for any human to be around.
When she becomes a Hakutaku, her clothes strangely change the color (and it's not part of her body).
Keine is the owner, and history teacher of the Human Village's school.
A usual mistake about her abilities is people mistake the ability of hakutaku-Keine as to be able to erase a piece of history; however, her ability in her hakutaku form is to create it, and in humanoid form is to eat (or conceal) it; fundamentally she can only conceal it, not erase.
As a teacher, she is commonly addressed by the respectful title of 「慧音先生」 or "Keine-sensei."
Keine is the only character in Imperishable Night to have 2 Last Word Spell Cards rather than 1.