Vague predictions of the future and lead one to adventure.
Saints and Sainthood: The inside story on the ascended
“Dreams are the only reality” suggests some of the ancient manuscripts. Dreams and the dreamers often reveal secrets long forgotten, or dreams can hide the truth only to make it resurface decades or even centuries later
A possible answer to what happens to spells when a mage dies. If the spell is strong enough, say and enchantment or other permenant effect, part of the mages spirit may become lodged in the magic. It may be a way for items to gain some kind of intelligence, but a mage who has knowledge of this fact would be very hesitant about enchanting anyone or thing. He might have other plans for his afterlife than counting the change in your bag of holding.
Preists, I think, would have this sort of thing covered.