Thassa's Emissary

Auras attached to a creature don't become tapped when the creature becomes tapped. Except in some rare cases, an Aura with bestow remains untapped when it becomes unattached and becomes a creature.

On the stack, a spell with bestow is either a creature spell or an Aura spell. It's never both, although it's an enchantment spell in either case.

If a permanent with bestow enters the battlefield by any method other than being cast, it will be an enchantment creature. You can't choose to pay the bestow cost and have it become an Aura.