For Chou-Chou, it seems that the VA has such a range that she is voiced by the same person in all forms, which is fine, and it's why I can't wait to hear her...I pretty much got 3 hints
As for Soul, it depends on how old they wanna make him sound I guess...Patrick Seitz and Troy Baker can pull off the older hero, and we've already heard Troy as Snow, so...he'd sorta work
If they're going for the younger voice, Shiloh Strong might work, along with Liam O'Brien (Though I see him more as an Elka (spelling?) than a Soul...it's kinda hard to pick without seeing more of Soul's personality
How could they NOT use Grant George for Elka? He's a Mid-Boss clone and he knows it.
Shiloh Strong won't happen, I don't think he's done anything in years... also he sounds like a black guy to me, which isn't wrong at all but voicing a clearly white character is off-sounding to me.
It's strange... I either want JYB to use his higher voice for Ryuto, or his lower voice for Soul... but not be both... Okay, got it. JYB's deeper voice for Soul and then Spike Spencer for Ryuto. That'd work for me.