IIRC, even when very angry at White or referring to him in the third person (as when he was discussing him with Hank and Gomez) he called him always "Mr. White."
If I am correct, I think at first it was out of habit and residual respect for a former teacher (even though they did not seem very friendly and Jesse was not in general respectful towards him -- he did however respect his knowledge and intelligence greatly) and later on purely out of habit because he was otherwise disrespectful (even physically attacking more than once).
I think Jesse was the only character who did this.
Note: When I was in HS one or two upper classmen called a teacher by his first name -- I did not think that was right, just as I thought it extraordinarily weird to call parents by first names. One of my cousins actually called my venerated (at least by me) grandmother by her first name, not to her face (she had passed away long ago) but in a conversation. That really rankled.
Certain conventions exist for a reason. I was in a restaurant and heard a waiter very seriously refer 2nd person to the owner/chef as "chef" and I see the value in this since the waiter takes time-critical orders from the owner. I mean, he used "chef" instead of the owner's first name, like a military rank.
Not just names but other things, like why temp employees, even of long standing, in general do not get offices (unless every FT employee already has one).
The military is incredibly serious about stuff like this and while I am not positive, an enlisted man calling an officer by his first name I think might, even if it is a slip, might get time in the brig. The "no fraternization" policy in most militaries is also completely serious.
The military worked all these things out, the goal being to make sure the chain-of-command functions.
It could be that Jesse at first called Walter "Mr. White" out of habit once they started working together but when Walt got Tuco to pay up, perhaps Jesse saw the value of Walt being the boss and so treated him this way.
I do not recall how Fring was referred to by everyone. His restaurant employees, without a doubt never, ever called him "Gus" but Walt did; I forget what Mike did. Fring is not the sort of man one calls by first name without explicit permission, I think.
