Quexinos welcome. You said -
. . . using God's name in a haunting situation can be powerful enough to get rid of the ghost/demon/whatever. Is this actually true?
The JWs make stories up like this all the time and they almost always fit their agenda.
For instance when I was a JW I was told that a nearby house was experiencing "a posession" not unlike the one in The Exorcist. Visiting JWs identified an old Christmas tree in the attic as being the source of attraction, and by removing the tree the terrible entity was out of there in a flash. The story enforced both the reality of demon posession and the evil of Christmas in one. JW bullsh*t. It wouldn't have made a very good movie either.