I just figured out how everything can be neatly tied together but I know it won't happen. The federation doesn't really care much about Christella Revi. After all she's used Earth as a base for decades with nothing turning up even though she's committed atrocities and mass terrorism for years. Just a few months after a handful of Altan investigators look into the only inhabitable planet in the star system, now the military, church, and even ancient empires get involved.
Oh and has Christella Revi's race ever been mentioned? We're lead to believe she naturally resembles humans so it's safe to assume she is also an Altan, but I don't think that was ever explicitly stated unlike with Gomez. That would also tie everything together.
Christella Revi has been more or less building an expendable army of spirits users and androids using the Japanese miltary through her cult. She has also hijacked the network of aliens, mostly Altan refugees who easily blend in with humans. Oddly all of these efforts are laughable as both spirit users and Earth made androids are repeatedly shown as hopelessly outmatched by a federation officer let alone military personnel. Is it all some kind of long game, working towards a breakthrough?
Either Christella Revi is trying to acquire some lost Altan technology that could completely decimate the federation or the federation is trying to justify marginalizing Altans claiming they are conspiring with Christella Revi/trying to revive their empire. But no this would make too much sense.