I agree on the fact that "public perception on the word plays no small role". I personally am not sure which name is better. Please think of my article as a proposition to be discussed.
Moreover, that is a general purpose of every article: to propose something to be discussed and not to state it dogmatically. I am sad that you have not published your chats. Maybe I would have written a different article. That said, a chat is not an article, nor a discussion, for that matter. The crucial difference is that an article is a published and structured train of thought which states something and proves some point (or at least tries to), while the chat is unpublished freeflow thought exchange (important in its own right). I have personally discussed many things over chat with many people. However, I cannot call it for that reason "a contemporary discussion". It has to be published, structured and known by the community in order to name it a "contemporary discussion". Again, a chat between likely minded people or friends does not qualify as a "contemporary discussion". Again, I am sad that you cannot point me to online articles, or at least forum posts, which exhibit contemporary discussions and contemporary pixel art definitions. I have written my text precisely because I did not found any on internet. I was motivated by the lack of theory on pixel art. And I wanted to open a discussion like this one.
"Does the grid follow from the properties of the pixel, or does the pixel follow from the properties of the grid?" Well, the pixel is simply a picture element. The name does not state nor imply that the picture element hast to visible to the naked eye or to be a perfect colored square that fits a grid cell. That is why I think "pixel" is not a sufficient word to describe pixel art. However, I agree on the fact that the idea of cell/field is logically connected to and even equivalent to the idea of grid. Simply put, one implies the other. So, I could have said also, let's call it a cell art. However, pixel is not a same thing as a grid cell. Pixel does not imply grid.
I agree that "grid art suggests that he'd [artist] be primarily concerned about manipulating the properties of the grid, in geometry." That is why I opened this discussion: in order to be englihtened about the deficiences of concepts I propose. And this indeed is a deficience of the name I propose. Still, it is less imprecise than "pixel". What is more, grid, in my opinion, suggests certain rigidity and regularity, and two-dimensionality, unlike, for example, the word mesh, which describes perfectly 3D geometry.
"The tendency has been to expand the meaning of pixel, beyond one single specification, instead of getting rid of the namesake". That is exactly what I am trying to do with my article. I will repeat, for me, a "pixel" in pixel art is a square of paint which has to be visible to the naked eye and has to fit the rigid, regular 2d grid cell perfectly. Than again, I would be indebted to you if you could point me to some less ephemeral than chatterbox internet resources for the pixel redefinition.