Warning: This post contains many topics not necessarily in order. I numbered my paragraphs so I can track myself. Please feel free to shoot it full of holes.
1. In Chapter 561, it's convincing that Mihawk has CoO. Luffy dashed through a crowd of fighters with Gear 2nd, and Mihawk still cut him. However, it may be his excellent hawk-like vision that allowed him to follow Luffy's movements.
2. When Zoro heard the "breath" of things around him, it could be rudimentary CoO. If he hones his perception, he'll hear the whole "voice" of things.
3. When Rayleigh said Roger could hear the "voice of all things", I think that meant Roger's CoO reached the level of prophetic ability, and ESP. I wonder if his CoC reached the level of "command of all things".
4. And considering Roger's proficiency in Haki, he may have used Haki to the point his body was damaged. Of course, I, from a Oriental medical view, mean his chi circulation becoming damaged because of overexertion.
5. Anyway, I'm certain Mihawk can hear the "breath" of things, if not "voice", because it seems that slashing through air, ice, rock, and steel requires sensitivity to "breath". It's not too unbelievable that Mihawk can hear "voice".
6. I recall in an SBS, Oda "chastised" a fan for not seeing the "fire" of Sanji's heart. This "fire" manifested as Diablo Jamblé. That fire may have manifested as a type of CoA. Boa Marigold covered herself in flames when fighting Luffy, it's pretty much set as Haki usage.
7. In addition, both Boa Sandersonia and Marigold used Haki to control their hair's shape and hardness. I believe it's the same as Seimei Kikan that Rokushiki users perform. That may be a combination of CoA and CoO.
8. When Blueno commented that Luffy learned Soru just by observing it once, that could be hinting at Luffy's CoO development. It could mean extraordinary vision leads to CoO.
9. In addition, due to the blinding speed of Soru in close quarters, catching the opponent may be an act of CoO. Similarly, Shakushi, as used by Captain Kuro, is the same as Soru, but without control, and Luffy caught him.
10. On the Baratie, Pearl set himself on fire. How that is possible relates to his experience of surviving in a jungle. Seemingly random, it could be a Chekhov's gun to CoA. And we know how Oda loves to use Chekhov's gun tactics in his manga. (Chekhov's Gun is a TVtropes.org term for the placement of a seemingly random and/or insignificant character/object early in a story just to have its significance blast in the audience's faces when they realize it)
11. I think further categorization of Haki is definitely in order. First, pre-CoO and pre-CoA are needed to categorize amateurs who have rudimentary grasps of their senses and strengths, but have not fully formed Haki. Second, further classification is needed for CoA, since fire control and hardening aren't necessarily the same thing. Boa Sandersonia couldn't handle Marigold's fire. Seimei Kikan may need a fusion classification, because it doesn't fit any category entirely. Roger's bizarre usage of CoO may indicate that extraordinary reading and prediction ability is related to CoO. In addition, theoretically, CoC controls the hearts of people, the simplistic usage makes people faint. If he combined CoC with CoO, maybe he creates a fusion category that commands the "spirit of adventure" to pirates all over the world.
12. Shirahoshi may have CoC, which she combines with Mermaid Calling, so that she can command Sea Kings. She may have also inherited CoO from her mother, due to an unusual sensitive personality.