What do the final paragraphs of the story contribute to the story as whole?"A Rose for Emily"
The final paragraphs of the story, in which they enter and examine the closed room after Miss Emily's burial, contribute greatly to the story A Rose for Emily because it provides confirmation to all the assumptions that the townsfolk, as narrators, have been putting forth to the reader.
The plot of the story had been building up suspense as to how Miss Emily's awkward behavior had been deteriorating and making her secretive and even more elusive. Her relationship to Homer, his sudden disappearance, her purchases as if they were married, and all the assumptions made on such behalf serve as clues to solve a mystery.
Those last paragraphs are the pieces that put the puzzle together.