"A non-being (also known as a Non-Human Spiritous Apparition)"
Isn't it the other way around? Non-Human Spiritous Apparition sounds far more likely wizarding term for these foul creatures.
The other "non-being"
Is it any good that this page be renamed? Aside from the type of being, "non-being" also describes the non-existence which awaits vanished objects, per McGonagall's explanation. There's at least one link from non-being used in that context pointing to this article. Omnibender - Talk - Contributions 00:04, August 14, 2013 (UTC)
You should add something about patronus' because I feel like theyre a really important part of Harry Potter and what a dementor is and how to overcome them and stuff