It's said he learns CoA from fighting the assholes on the island off. People infer with an educated guess (but still not said or confirmed until Oda says anything) that CoO probably came from survival, like trying to keep watch when sleeping, otherwise if running for 2 tears when Iva said day and night he'd be chased, how did he sleep.
For names, might have asked about the skills he developed after developing them or seeing them like Luffy asked about CoC after unlocking it. But that's not being taught how to use it.
Learning by observance isn't the same as being trained if the person didn't specifically set out to train you. A person only has their own quick thinking, observance, and adaption to thank if they learn that way.
If you watch someone play chess and learn through observation, or get better by playing them, you think you suddenly have to credit them as a teacher? Fuck no! Especially if they acted like a predator as you played them.