I believe this title is meant to sound like "A Tribute to..." I usually have my class brainstorm what kind of a story they think this is going to be, based on the title alone. The most common answers are: "Romantic," and "Somebody dies." When you think about it, these are two pretty good summations of the story. I think the title is meant to be foreshadowing, but also cryptic. It is, after all, modern Gothic Literature.
Consider what you already know about tributes to people after death. They are done in a spirit of reverence and usually great respect. Details throughout the story seem counterproductive to reverence and respect for this woman who seems to hide so many weird (to say the least) and twisted secrets. But based on such a title, we continue to read with some sense of hope that she deserves the rose at the end. This title sets a perfect tone to build the mystery and suspence, and even succeeds in allowing Emily a bit of dignity in her death, despite the gruesome way in which she is found.
The title hides most of the answers to your questions. To simply call her miss Emily would be to create an artificial barrier to what the author intends people to feel about her. He simply called her Emily as a term of friendliness, and warmth, plus familiarity. That the author feels pity--but not a strong sense of it-- for her is obvious. He rewards here with one rose, not a bouquet that people receive for great performances. The fact that she gets one rose indicates how difficult her life has been and how troubling life was for her. But, she is entitled to a rose and that says much about her ability to at least take charge, do something about her situation, even though she chose wrong.