We cruised the Fantasy the first week of March and they had a full Catholic mass daily at (I believe) 8am in the Buena Vista theater. I went twice and it was very nice.
They also had an interdenominational service on Sunday for all.
Have you checked out any posted sample navigators here on the DIS? That's where I would look as that's how I found out about the Fantasy's services when onboard.How can I find out if religious services are available on the Dream?