Most likely.

I don't think so. I'm fairly certain that Shinjiro Senpai vapes though :D

I can confirm that Teddie vapes. TV world is foggy for a reason.

No wonder the shadows get pissed when the fog lifts, they lash out at anyone there because they think it was them doing the vaping...

So in other words the events of Persona 4 are all Teddies fault... and Yosuke because its always Yosuke's fault.