Maco is by far the most relevant YC1 in the series while King is responsible for a drastic shift in the story's dynamic via Seraphim. It's not that they're not special enough to get awakening or CoC, they don't need those to be special because they're more special than awakening/coc users due to different reasons.
No they aren't tho
Marco having a Phoenix fruit and king being a lunarian dont stop them from being conquerors or stop them from mastering their fruits or stop them from having some type of haki mastery
The reason they don't have those abilities isn't because they're too special its because they aren't special enough
Like not every lunarian is going to be important, relevant, or even strong. Same thing with people with mythical zoans
Being a conqueror is something that automatically makes you stick out more than anyone else without it
Mastering awakening is going to speak alot for your skill especially in comparison to those who cant achieve it