I didn't really get the yoga instructor exchange. Was it just a nod to the stereotype of them being flighty because while I can see that, I still think they know yoga and what it's about. It was just a weird scene. In fact, this whole episode was weird scenes, with the principal stuff and the scene changes (which I liked). It's like they had some random ideas for scenes and cobbled them together here.
But, thinking about it, that may just be the Family Guy MO now anyway and I just noticed it because it's been awhile since I've seen a new episode.