The "we" is communal by definition, but I would argue the "we" proceeds from a singular person linking himself with the town as a whole. The voice is that of a gossip or self-appointed town-historian, lending the story an oral quality, which is also enabled by the circuitous (or at least unchronological) ordering of events. If the "I" is behind the "we," the question of gender then presents itself: is this a man or woman speaking, or is the voice sufficiently distinctive to leave such a trace in the text? I would argue that the voice is male, although that is an intuitive rather than strongly reasoned response, based in part on the way the narrator describes the townsmen investigating the smell around Emily's house: who could tell a lady her house smells, the narrator asks. Well, I don't think a woman would say that; I think a woman would wonder why no one confronted Emily with the smell. This is just one instance of several small clues that suggest this might be a male voice speaking for the community.
The point of view is actually first person plural - it is written from the perspective of the townspeople. This supports the story in a few ways. First of all, it allows for the surprise and shock of the ending. The townspeople are on the outside watching Miss Emily and have no idea what is really going on inside her house. They gossip about her but they don't know, so at the end, the reader finds out the horrifying truth at the same time that the town does. Also, the point of view shows how isolated Miss Emily was. She is an object to the reader, not a character because the reader never gets to see her thoughts or hear her speak. Miss Emily's isolation is one of the key reasons she lives the way she does and ends up killing Homer.