There are several hints the shows that the Church in Alkubra is not the only Church to praise Man of Zinc, but that there is a Church in the Federation with even more influence in the whole Caravaneer world.

I will use spoilers here, if you people don't mind:

• When the Federation Army kidnapped the Bunker people and stole them nuclear warheads, they executed Emilia's baby performing with excellency a ritual learned only by the Church's demon hunter, as told by Jacob Fulier.
• Solanum III, The High Priest of Orth reveals to the very favorable to the Federation and afraid of Qubba if asked about. He probably knows about the Federation faith.
• Shosta have a building that are very similar to the Citadel of Loneliness in Orth and the temple in Confusion. Maybe its a church colony like Confusion.
• Kukul said that his family leave Qubba for being persecuted for them religious beliefs, then they went to the Federation, where they were well treated, and then later Kukul leave the Federation and went to the Tribal Region as a missionary, where he eventually lost his faith. Kukul never reveal what his religion was, however. Maybe his faith was in the Church and his family was well treated for share the same faith with the government.
• John Sheppard use some Churh mannerism in his dialogues, implicating that he is a follower of the Church too. Since he never used such mannerism in the first Caravaneer game (and maybe the religion do not existed yet), he probably converted himself to the Church some time between the events of Caravaneer 1 and Caravaneer 2 games. Its unclear if he converted himself during or after he was president of Qubba or before, during or after the Church being persecuted in Qubba.
• Dolland Truffle shout "Sweet Man of Zinc and Santa Lois!" when the player complete the fourth Workforce Merchants mission, implicating his faith in the Church. However, the Church shows no influence in Janubi region at all, where the religion gives place to the political conflict between the capitalist Janubi government and the socialist Ozbet government. Dolland probably converted himself in some business trip to Ausz, as he don't seem very likely to travel to Alkubra, leaving the region to be managed by Calvin.
• The Federation flag has the very symbol of the Church inside its triangle - the same symbol have is showed in the High Priest's hat in Alkubra.

However, the possible Federatio church is never explicitly cited in any part of the game. The "Federation Church of Man of Zinc" truly exists in the game, or its just some fandom? What D-mas' opinion?