There are several detailed essay topics already available on e-notes: here are a few more -
1) Analyse the positive and negative effects of using multiple narrators to tell the story.
2) What does each character gain from the journey to lay Addie to rest? Which character gains the most?
3) How would key events in the novel differ if told from one perspective? Review a chosen section and re-tell in the third person. Present a commentary on your writing, highlighting the effects of objectivity and subjectivity on the events selected.
4) How would Cash choose to represent the final events of the novel?
5) Do you consider Darl to be sane or insane? Chart his emotional development/demise through the novel and reflect on his own viewpoint as well as that of other characters.
6) Write a continuance of the novel showing the reaction of one of the children to the 'new' Mrs Bundren. Try to emulate Faulkner's style as well as keeping the content plausible.