In the long term I would be more worried about Martian Orthodox calendar concerns. The natural year of Mars is almost twice as long as Earth....and tying Pascha to Martian lunar cycles would be beyond pointless. If care is not exercised, in a generation or two you will have Old Earth Old Calenderists, Old Earth New Calendarists, Martian Old Calendarists (those who organized the Martian Calendar from Julian roots), and Martian New Calendarists (who just started over, blank slate).
For what it is worth, I'm in the middle of writing a Science Fiction story for a major SF market contest premised upon a Martian colony built by a one way advance team of Russian Orthodox monastics. The what happens when Jesus comes back is a discussion I hope to embed somewhere if there is room and an appropriate place. We'll see how it all works out in a few weeks.