Korra's voice feels spot-on to me and I love everything she's done so far, I am very excited to have her in the game and see what kind of CR she builds and how you incorporate upcoming new canon to her as well.
I can't think of crit on the others, except I feel it's a shame Hook missed out on the last event. He keeps being very laid-back or shying out of participation in most large events or logs that happen and I think it hurts his chances at bonding with others. I know you've often said you struggle with his voice, but I think the only way to get comfortable with him is to get him out there and get the chance to play him more often and in more varied situations.