A few twists and ideas for the 'alternative religion for Russia(s)' meme who is at times around...
Your challenges, if you wish to take it, is to end like...
A. A muslim but SHI'ITE Russia...
B. A Russia converted by Georgian church or perhaps Armenians OR even Nestorians missionaires.
(disclaimer; I don't know the subtilities of those christianisties much... are georgians or armenian churches orthodox, 'oriental'.. My apologies if I offend.)
C. Somehow a form of ZOROASTRISM. (ASB, I fear).
Note; this can be a local 'russia' state as an Ukraine - a part of a never united Russia, or an odd local culture like Russyns for Ukrainians, Hakka chineses...