With Killer up there it's very likely that he's able to cover his blades in haki, otherwise he does not even have to try. And by extent Kid can most likely imbue his metal with haki aswell, so both are likely adv CoA users.
I think the reason why Killer is a pretty good support in that fight is, that he got stats on the level of the rest, while he's agile as fuck.
If he ends up imbuing his blades with haki, he would basically be a (stat boosted) Kimemon that dodges their swings with that gymnastic stuff.. Not even half bad tbh.
2 problems with that though:
Why not use haki on your blades against Zoro?
And if they are able to hurt Kaido, how did their first encounter could have played out the way we were told (letting them play until exhaustion) ?
Hmm..