Zkk was a prediction too.
They are on our ass for more than a year now.
Zoro killing Kaido was a stupid theory, it had no foundation. It denied the fact that Luffy was the main character, not Zoro.
Zoro knocking Kizaru out is possible, there are multiple arguments for it.
- Luffy already defeated Kizaru once (temporarily) and Zoro may face him as well (we had the same thing with Lucci)
- Luffy will defeat Saturn (whole arc is building towards it)
- Zoro always follows his captain and may defeat Kizaru
- Luffy defeating Saturn gets him a >4b bounty, Zoro defeating Kizaru gets him a 3b bounty
- Zoro said he would even cut "light"
- Egghead is perfectly mirroring Sabaody so far
- In Sabaody, Kizaru knocked out Zoro
- In Sabaody too, swordsman and "Dark King" Rayleigh clashed with Kizaru with his sword
-> "King of Hell" Zoro may clash with Kizaru and knock him out (perfectly mirroring Sabaody)