Perhaps I'm not coming up with the right term here but let me explain my experience.

HB I'm interested in sits next to me in class and gives me some grief about stealing her seat or something. Sort of a non-factor but an FYI

So I have a pretty good rapport with my prof. and this class in particular she was calling on me and highlighting my work. I cant exactly remember how I was handling it it but I was doing it all with a smile on my face, which I figure is always a good sign.

Back to the HB, almost every time I had an exchange with my professor the HB would quip back something, even on conversations she wasn't involved in.

Is this a DHV scenario or am I just crazy?

Depends on whether or not anything she said was good or not. Whether or not it made sense. If it was good, it was probably genuine. If it wasn't, it was probably ingenuine.

Ingenuine = more likely to be attempt to DHV
Genuine = probably just rolling with it. Could be either intential DHV or simply classroom participation. I'd say the frequency is the key here. She could also be attempting to DHV because she wants your attention. Not all DHV's are rooted in rejection

Regardless, mystery has been created. Take a step back and allow it to unroll, jump in when ready. Sounds like she could be a smart cookie though if it's intentional. Beware if you find she's only looking for power.