That seiyuu cast...they really went with quite the predictable list. Kaji for Daichi, HanaKana for Io, even Ishida for AO.
But Joe's and Keita's seiyuus come as a bit of a surprise. I always imagined Joe with a younger voice than Sugita's, and Keita's with deeper one than Kakihara.
Edit: As for Hibiki, I won't be surprised if they got Mamoru Miyano for him.
Edit 2: My bad I didn't read it was a prediction. Those predictions are pretty close to mine though.