I don't know, I didn't quite see KH3 being released in 2017 even before the delay. I feel like we don't know anything about the game yet, so they'd kinda have to throw a bomb in our faces like "heyy guess what?! Secretly, we're already finished developing KH3, ayyylmao."
Yeah, I think 2017 is going to be the KH3 hype year. We're probably going to get more trailers, see some gameplay, more world announcement etc. Gotta remember Ux isn't ending any time soon either, there's still the second season to go and I doubt they're going to release KH3 before that's all done.