User blog comment:Boy-Yo/Funimation voices for the last two Yonko?/@comment-1595565-20170307223740

For Kaido, I doubt it will be Travis, he's since moved away from anime. With the exception of the Supernovas, Joel has been casting local as of late. I doubt he'll want to recycle Swasey, Massey, or Mathis considering who they play, so my best guess would be one of the older guys you don't hear much about, like Grant James. Mark Stoddard is also a possibility. R. Bruce Elliott would be the longshot, since he could pull it off if he went gruff and nasally. The only other possibilties I can think of if he doesn't cast local are Neil Kaplan and Kirk Thornton. Now that I think about it, Kaplan could be a frontrunner.

As for Big Mom, Linda Young is a possibility, as is Tiffany Grant. Jamie Marchi is also a possibility with maybe a touch of post, since she has the natural pitch range necessary without trying very hard. I would add Monica Rial, but I'm not sure she can get her voice deep enough without wrecking her throat.