Fnygirl, I'd say that it appears you have the upper hand now! Congratulations! Think about that, smile to yourself about how totally bugged she is, and let that knowledge help you firm up your new spine!
I have to wonder, though, if perhaps it's more people than just you who have decided to dial waaaaay back on their 'friendship' with her. Seems that for having virtually no contact for the last several months, she's awfully obsessed with your comings and goings now. And making the comment about not knowing that you two were even friends....weird. What's it to her? So that makes me wonder if some of the others in the neighborhood have been giving her the cold shoulder too, which may have prompted her to start her 'surveillance' of not just you, but maybe some other people. No proof, but just a thought.
Question: before you saw her for what she was and started trying to actively avoid her, did you two do things together, one on one, or was it just as a part of a larger group?
Did your LunchNeighbor give her much information? And what did Bully tell LunchNeighbor about why she even asked about your lunch? I mean, that question was just outright nosey! I'm really curious to know how she spun her question or even her whole conversation with LunchNeighbor so she didn't sound like a horrible busybody!