The Bible condemns divination, necromancy, soothsayers, sorcery, spiritism and witchcraft, identifying all these practices as abominations, based on demonism.
True Christians do not celebrate Halloween. It is pagan in origin and practice and will destroy one's relationship with God. Light and darkness cannot mix.
A prophet is one who speaks for God, expressing His will in words and sometimes signs. Standing outside the system, he proclaims God's purpose, including repentance.
Balaam, motivated by self-interest, believing that the ends justify the means, willing to do anything to get his way, is spiritually inferior to a donkey.