I'm one! Seventh Day Adventist. Not that that's directly related to the question... There's not so many in Britain though. and I haven't heard of any services on Titanic that would relate to that. So I don't think there were any services specially, in all probability!
I'm a Seventh Day Adventist also, and I don't know for certain that there were any SDA passengers aboard Titanic, but I've had suspicions about Dr. Alice Farnham Leader - though I've nothing to base it on.
However, there is nothing to indicate that there were services for Jews or Sabbath-keeping Christians aboard Titanic.
I recently found a couple of obituaries of Dr Leader's husband. He was a Catholic and active in the Knights of Columbus. That Dr Leader's funeral was, according to her obit, said by a Father O'Farrell would seem to indicate that she converted to her husband's religion.
My family is seventh day adventist and I just happened to stumble upon a video claiming to have Adventists on the Titanic, which was very interesting because my Great-grandmother had a ticket and ended up missing it. (We still have the ticket--- somewhere).