Man, that's a really tough question...

The truth is, I never really cared all that much about voice actors. By that I mean, I don't care WHO voices which character. I don't have high expectations so I'd accept almost any voice actor. The only people I DON'T want to voice-act characters are those Hollywood celebrities, like Chris Pratt. I'd rather take complete amateurs over some celebrity or popular youtuber.

As for Q-Taro, it's kinda hard to imagine which voice would be the most fitting. I really liked Thurop van Orman's performance as Flapjack in "The Marvelous Misadventures of Flapjack"; his voice is basically angelic! I also liked Lara Jill Miller's voice as Henry Hugglemonster in the show of the same name. So, I guess voices similar to those two would fit pretty well for Q-Taro? Whatever it is, I much prefer a woman doing a boy's voice than an actual boy doing a boy's voice (not sure if that makes sense, but it's some quirk of mine). I have no idea for the other characters though...