2018-12-07 : An instant or sorcery spell is not a creature spell, even if that spell creates creature tokens.

2018-12-07 : If a creature spell has generic mana only in its alternative or additional cost, the creature will still gain haste.

2018-12-07 : If the mana is spent on a noncreature spell that becomes a creature later in the turn, that creature won’t have haste.

2018-12-07 : If the mana is spent on two different creature spells, each of those spells (and resulting creatures) will gain haste until end of turn.