Well, I can't think of just one character.
Hinata's voice is sweet and mao chan's voice from chibi devil is sweet.
Do you have any other character in your mind, Minasan?
Uh....Not everyone can pull that off.Even a chibi voice doesn't sound natural.
So, I don't think voice actors do much. It's kinda like a natural talent.
I might be wrong but that's how I feel.