Enter the Tolkienologist. (Self-taught, naturally.) Registry #21187 (birthdate).
Where did you post about the British accents? Here at CC?
Its not news to me. And even someone who's only watched the movies ought to know.
And yes, the Ainur (plural, as opposed to Ainu, singular) is a collective name for the Valar and Maiar, as well as those spirits of the same nature who remained outside of Ea, and also to those who, while once Valar and Maiar, are no longer generally counted as a part of those orders, due to rebellion. (That is, Melkor/Morgoth, and his minions, notably Sauron/Gorthaur, the Balrogs, and Ungoliant. Shelob is thus at least partly an Ainu's offspring, as she is of Ungoliant's progeny.)
Since the wizards were emissaries of the Valar, disguised members of the Maiar, Gandalf, Saruman, and Radagast are Ainu, in addition to Sauron and the Balrog, giving us a total of five Ainur who figure into the LR.
There's also Shelob, and Gwaihir the Windlord for Ainu-related creatures.
Sorry about the preachy post. Its Tolkien, I can't help myself. Those of you who are freaks like me know it anyway, and those of you who aren't will forget it immediately. Oh well....