Halloween is one of my favourite times because it allows us to step out of our present human existence and find an identity and/or a life somewhere else. Such a condition could be heavenly or hellish, however, it's up to each individual to choose his/her afterlife state.
It's hard to image that one could have fun as a zombie or vampire, but it beats being nothing or just human. If things don't work out in the afterlife, you can always get a job haunting fun houses in Niagara Falls. Many people will pay good money for a good scare.
Sure there's past lives, but there's past deaths too. The soul can continue to survive and go on to something else. At Halloween, that choice can be very unpleasant and scary. Have fun tricking and treating.