I was one of the people that used to believe that Kidd, Boa, Admirals/Garp would have CoC/CoC coating but not anymore, Admirals shit their diapers everytime they sense someone's CoC, Boa was completely useless without her DF, Kidd has no talent for haki. Luffy and Zoro training to improve their haki meant something and I doubt we're going to see characters that have never been big haki users show up with advanced forms of haki.