Bazaar Trader combo and Void Snare - Ownership vs. Control
As you note in your title, there is a difference between ownership and control. 


  110.2. A permanent's owner is the same as the owner of the card that represents it (unless it's a token; see rule 110.5a). A permanent's controller is, by default, the player under whose control it entered the battlefield. Every permanent has a controller.
  110.5a A token is both owned and controlled by the player under whose control it entered the battlefield.


So clearly, we know the owner of the card, and where it goes as a result of void snare.

But let's say, for some reason, it said controller's hand instead of owner's hand. That's already covered: cards only ever go to their owner's hand.


  400.3. If an object would go to any library, graveyard, or hand other than its owner’s, it goes to its owner’s corresponding zone.


As for who the owner is, well that's also defined for us:


  108.3. The owner of a card in the game is the player who started the game with it in his or her deck. If a card is brought into the game from outside the game rather than starting in a player's deck, its owner is the player who brought it into the game. If a card starts the game in the command zone, its owner is the player who put it into the command zone to start the game. Legal ownership of a card in the game is irrelevant to the game rules except for the rules for ante.