Decoy Gambit

• WWizards of the Coast2020-04-17
  Official Ruling
  As the Decoy Gambit resolves, first the next opponent in turn order (or, if it’s an opponent’s turn, the opponent whose turn it is) chooses whether you’ll draw a card or return their creature that was targeted to its owner’s hand, then each other opponent in turn order does so knowing the choices made before them. After all choices are made, you draw the appropriate number of cards. After you’ve drawn, the appropriate creatures are all simultaneously returned to their owners’ hands.
• WWizards of the Coast2020-04-17
  Official Ruling
  If a creature targeted by Decoy Gambit changes controller, it’s no longer a legal target.
• WWizards of the Coast2020-04-17
  Official Ruling
  For each opponent, if you didn’t choose a target creature they control or if that creature has become an illegal target, that player can’t choose for you to draw a card.

Rulings via Scryfall