Ok let me explain two things:
1. The reason Kaido says to the scabbards and Zoro that they are using Odens Ryou is because he feels like its a similar Haki. As in it gives off the same feeling. Its not meant to be taken literal. You cant use a Haki of a dead person its impossible. What Kaido felt is the scabbards haki. Which was omitting a similar feeling to Odens Ryou.
2. Zoro unlocked CoA in alabasta there is alot of proof. He just didnt understand it fully yet and couldnt fully control it.
Luffy and Zoro were both exposed to Haki in the childhood but never understood it really. At alabsta Zoro used haki for the first time but it wasnt something he could use at free will yet. And only mastered it at a high level in the time skip.
Finally someone who have brain....
These zoro haters are insane man, they have to downplay every panel of zoro doing things
I cant imagine how rotten their brains are....
Imagine if oden or some powerful people haki can be carried over their belongings.....
Luffy's hat will be indestructible because rogers haki is in that hat.... or ryuma sword will cut oars in halves..... wtf is zoro haters thinking?...geez