Pretty interesting choices you got there, pal! I've listened to Griffin's clip for Akira, and I think that sort of voice could fit Takuya and his Spirit forms—especially the latter, if it was tweaked to sound a bit lower and gruffer. However, I'm curious as to how his Nate voice sounds; would you please post a decent link? As for Clifford… I have to say, his Cabba could fit Takuya as well; and for the Spirit forms? I think his Bakugo voice would pretty much seal the deal. Never thought of them before, but again, they seem interesting. Another choice of mine for Takuya, way before deciding to pick Antony, was Jason Griffith, using his Sonic voice.
Speaking of Clifford, though, I've been recently considering him for
Keisuke Amasawa/Amazawa, the player character of
Digimon Story: Cyber Sleuth – Hacker's Memory (long name, I know). My other choice for Keisuke would be Max Mittelman (Kousei Arima/Harry Osborn).