The Seething Song/Sudden Spoiling question is answered incorrectly. Rules state:
702.36a. Morph is a static ability that functions in any zone from which you could play the card it's on, and the morph effect works any time the card is face down. "Morph [cost]" means "You may cast this card as a 2/2 face-down creature, with no text, no name, no subtypes, and no mana cost by paying {3} rather than paying its mana cost." (See rule 707, "Face-Down Spells and Permanents.")
Morph is not an ability of the creature, Sudden Spoiling does not prevent it from being flipped.
702.36a. Morph is a static ability that functions in any zone from which you could play the card it's on, and the morph effect works any time the card is face down. "Morph [cost]" means "You may cast this card as a 2/2 face-down creature, with no text, no name, no subtypes, and no mana cost by paying {3} rather than paying its mana cost." (See rule 707, "Face-Down Spells and Permanents.")
Morph is not an ability of the creature, Sudden Spoiling does not prevent it from being flipped.