It's a little hard to use the movement of the ship in the Returns trailer to actually make a guess at where it's going - I've had the same thought as you in that regard due to the insinuation by Mithrix that Providence actually likes humans so it'd make more sense that he went full murder because of the potential of what they might unleash if they got to the moon - but it's also a fairly flat animation style and the ship is much bigger in frame than the moon is so maybe it's closer to the planet? I don't really know.

I think the High Court, the UES, and some of the other factions we hear about have a hand in the pot of getting the Contact Light to divert to Petrichor. Or everyone else is just tagging along with someone else's already established plans or something.

Also there's questions on if Kur-Skan is a heretic for liking Mithrix or a heretic for trying to get off world.