My suggested new ending (spoilers)
Out of guilt and shame for Lavinia's death, Emily hangs herself and leaves a suicide note.
Sue, realizing what a terrible, hysterical idiot mother she is, locks all of the kids responsible for Lavinia's death in a shed and burns them alive, with herself inside.
Why should Emily get any forgiveness and redemption?
People who bully others into suicide should have their lives ruined forever - jail, no college, blackballed from decent society.