The trinity part is tricky. There are scriptures both for and against it implying that there were two different strains of beliefs mixed together. The doctrine of spiritual correctness states that those who do not believe in one or the other will go to hell/die at Armageddon.
The cross versus pole issue would be unimportant if it weren't for the fact that JWs condemn it as a pagan symbol. This means that those who believe that Jesus died on a cross are going to be destroyed for picturing Jesus' death in the wrong manner.