Do I "control" creatures in my graveyard?
Rule 109.2 says


  If a spell or ability uses a description of an object that includes a card type or subtype, but doesn't include the word "card," "spell," "source," or "scheme," it means a permanent of that card type or subtype on the battlefield.


In its targetting clause, Cloudshift says "creature" without any of the specified words, so it's referring to a creature permanent on the battlefield.

In general, you don't control anything in the graveyard. Rule 109.4 says


  Only objects on the stack or on the battlefield have a controller. Objects that are neither on the stack nor on the battlefield aren't controlled by any player.


Effects that deal with cards in the graveyard would refer to their owner.