I remember reading another thread about a crooked tooth and the upshot was that as long as it's not causing the cat any problems -- any discomfort or problems eating, for example -- then it's merely a cosmetic thing.
As far as the choking and vomitting during petting, it sounds like some kind of an overstimulation problem. I haven't heard this particular one before, but you might just hold off on the petting sessions until you can have it checked out.
I don't know much about Himmies, but isn't having some breathing problems one health condition associate with the breed? Not sure, just guessing, maybe another member more familiar can filll us in.