Bill Farmer, the voice actor for Goofy in the Kingdom Hearts series, was recently interviewed on an episode of the "2 Men and The Mouse" podcast. The host asks Bill about his experience with the Kingdom Hearts series, and Bill explains the process and why he thinks Kingdom Hearts is so popular. Bill is then asked about recording for Kingdom Hearts III. He confirms that he has been recording for Kingdom Hearts III off and on for "years, now", thus solidifying his questionable tweet made last year in which he claimed he was finished recording for Kingdom Hearts III and that it would release in 2015. In this podcast, he again clarifies it was Kingdom Hearts III he was referencing in his tweet, and not one of the side games. According to Bill, since he was done recording, he figured the game would be released relatively soon. He is now unsure when the game will release, and is also unsure if he will be recording for Kingdom Hearts III again soon.
You can listen to the entire podcast here. The questions regarding Kingdom Hearts begin at 57:54, and the question regarding Kingdom Hearts III begins at 1:03:00.