Update 1: Thanks again to KHInsider for the find, we now know that Jesse David Corti actually Tweeted on February 8 to say that he had done some voice acting work for Neku on that day. This makes it pretty certain that he'll be voicing for Kingdom Hearts 3D!
Jesse David Corti, the voice actor for Neku Sakuraba in The World That Ends With You, has hinted at returning to voice the character in Kingdom Hearts 3D: Dream Drop Distance. Via a comment on one of his videos on his YouTube channel, Corti suggests that "you may hear me..." in the game. Since other voice actors have already confirmed their involvement, which means voice recording for the English version has already commenced, we can probably assume that what Corti is saying is true. Thanks to believe-it-ornot from KHInsider for the find, you can see a screenshot of this hint below. (Jesse David Corti is YouTube user dreamories.)