Beat the Church route now. The final battle had one point that forced me to reset, mainly it was the enemies on the right side of the map charging all at once that got me, the Aura Knight and Brave Axe Knight perfectly covered each other and created a no-win situation, so had to do a redo where I was aggressive from turn 1 and attacked in three directions at once. Still quite tricky when you're overstrung like that, but doable.
This version of The Immaculate One was tougher than the other one due to the higher range and the different terrain, although she didn't have that BS "I'll hit you with whatever you're weaker to" move.
In the end used Leonie and Byleth to man the ballista and Fire Orb, and then had Raphael, Caspar, Seteth, and Bernadetta ready to swoop in after the one-two crack from far away, while Petra did chip damage from an awkward corner while I moved everyone else in position. She ended up getting the final kill.
Final pairings:
Raphael-Shamir
Manuela-Ferdinand
Caspar-Petra (same as Edelgard route)
Mercedes-Alois (this is a weird one)
Byleth-Bernadetta
It feels wrong pairing Flayn up with anyone but I also want to see a future where she doesn't just wander off into history.
Murderer's row (though you kill four people in the Church route and there was probably a way to win over one of them)
Ferdinand -> Ashe (which makes him Ashe's killer in both of my Black Eagles timelines)
Byleth -> Lorenz, Edelgard
Raphael -> Hubert