Imps+in+eager+Caucus+Raffle+for+my+Soul!

This line is saying that some people may win this "raffle of souls", but the poet definately has not. When you think of the concept of hell, you might (at least I do) think of hordes of howling demons waiting four your soul to fall from grace and decend to the bowls of the earth where it can be tortured by them for all eternity. (interesting side note: this idea was orginally inspired by the Fates, of greek mythology, because they would cut your life string, and watch as your body was consumed by age and passed up for judjement.) Anyway, Emily was most likely thinking of this image when she wrote this; the "imps" representing demons, and "eager caucus" implying the frenzied manner associated with beasts waiting for another damned soul to devour till the ends of time.