In terms of "A Rose For Emily" and "A&P," are similar, with a few distinct differences. You can choose the one you wish to use.
We learn about the main characters in different ways in each story, in terms of the chronology of the story: "A&P" is told in the order in which the events occur; there is no chronology in "A Rose For Emily" as the story jumps around in time.
In both cases, the story is told in the third person (using he, she, they, etc.). And the narrator in each story concentrates on one character.
A major distinction is that in "A Rose For Emily," the narrator is a member of the community who is conveying the town's experiences over the years with Miss Emily. However the narrator seems to be using an objective point of view: writing simply an observer, sharing only what he/she sees, without bias. The difference with "A Rose For Emily" is that we never really get into Miss Emily's head: we don't know what she is thinking, whereas with Sammy, we do.
In "A&P," we learn about Sammy in a straightforward way: we do not know who the narrator is, neither is he presented as part of the story. In "A&P" the story is told in third person, limited; we know everything Sammy is thinking throughout the entire story.
In "A&P" and "A Rose For Emily," the narrator speaks to the reader in the fiction-writing mode—where the narrator speaks directly to the reader.