1. About the Valar
After the creation of Arda, some of the Ainur chose to enter it and dwell therein until the end of its existence. These Ainur were divided into two groups: the Valar and the Maiar (singular forms: Vala and Maia). The Valar were the greater spirits, and the Maiar were the lesser, in terms of ability. There were fourteen Valar, who could take on physical forms at will, which often though not necessarily resembled those of the Children of Ilúvatar, particularly the Elves.
The Valar did not really have sexes, since they did not have innate physical forms, but they are generally referred to as either male or female, and some of them did take spouses. The female Valar are collectively called the Valier. The greatest of the Valar are collectively known as the Aratar, the High Ones: Manwë, Varda, Ulmo, Yavanna, Aulë, Mandos, Nienna, and Oromë.
Although Men sometimes called the Valar gods, this is not strictly speaking accurate. Tolkien described them as "angelic powers," who ruled with delegated authority from Eru, but did not have the power of creation from nothing within themselves. Each of them knows somewhat of what is to be, from having seen an image of Arda in time before its actual creation, but they know different aspects and even together they do not know everything.