Marina del Rey
There is a distinction between playing a card from your hand, and using a card effect to "put into play" a card.
(1.16) The phrase “put into play”
If a card effect uses the phrase “put into play,” it means that the card enters play through a card effect instead of through the normal process of paying resources and playing the card from hand. “Put into play” effects are not considered to be playing the card, and will not trigger any effects that refer to a card being played. “Put into play” will, however, trigger any effects that occur when a card “enters play”.
Sneak Attack instructs you to "Put" 1 Ally "into play".
Fili + Kili's Response triggers when you "Play" one of them from your hand through the normal act of paying their resource cost.