I don't think ZKK is going to happen if Zoro gets a solo fight like King. Fighting King would require him leaving the roof for 3-5 chapters. maybe even more since Franky and Sasaki have been fighting for like 10. ZKK also would need build up, more then what we got in 1002 and 1003. Kaido needs to have his scar reopened, and recognize Zoro as a master samurai before ZKK can happen. CP-0 implied that the Straw Hats would defeat Kaido's executives.