Here we go again. Let's have some fun.
Enma doesn't store haki. It forces out more haki than the current user wishes to release if they can't control it.
Usopp won't Scar Kaido with enma. If the Scabbards can't control enma than a none swordsman like Usopp can't. Swinging a sword doesn't equal to controlling a sword.
When Zoro first attacked Kaido he didn't scar or even cut Kaido. He only bruised him. If enma was the reason Zoro scarred Kaido than each one of his attacks would have scarred Kaido. Especially, since you believe Usopp, a none swordsman, can scarred Kaido with enma. It's almost like Oda added that scene to shut up anybody who wants to claim enma does the work, not the user.
The strange haki Kaido feels is Zoro's haki. Kaido is familiar with Oden and his haki so he knows how it feels. He is unfamiliar with Zoro's haki because he has never faced Zoro before so Zoro's haki would feel strange to him.
When Zoro scarred Kaido he never mentioned Oden or Oden's haki. He only mentioned Zoro's haki (CoC) and gave credit to Zoro, not enma or Oden.
Zoro didn't know what Luffy was training in. They didn't train together so the first time he saw Luffy use his new power was against Kaido.
That was just his reaction to seeing Luffy's new power for the first time.
As we can see, Zoro didn't know what Luffy training. Which was different than Kid who didn't know the type of haki Luffy learned or the fact it can be used with physical attacks.
Go ahead and hold this, you deserve it.
:holdthisl: