If a creature is transformed into another creature (say, a human into a dog), then that creature will become more and more accustomed to the new form until a point is reached where reversing the spell is impossible. A second transformation is possible, but the creature will have to go through the whole process again.
An ancient, psuedo-immortal race has been manipulating something important (politics, religion, economics, etc.) for centuries. Hardly anyone is aware of them, let alone their goals.
Whistling on the sea is bad luck. It is said to mock the sound of a strong wind and will call it so nature can show the true sound. Whistling is only allowed when becalmed or when shrouded in fog.