Control magic+ Nephalia smuggler

[Pretch]

 {Control Magic} {Nephalia Smuggler}
If I was to use Nephalias ability on a creature I have control of because of control magic would the creature return to the battlefield under my control? While I'm at it, say I gained control of the creature with {Act of Treason} instead of   {Control Magic}?

[Agrus Kos, Enforcer of Truth]

I don't see why not

[Birdbrain]

If its exiled, the enchantment will fall off, however...

Yes. It says in the text it will return under your control. So it will