I actually think you can get through Blue Lions without actually killing anyone from the Monastery. Edlegard's path on the other hand... well if you have trouble with offing named units that may not be the path for you.
I managed to pull it off with only losing Bernadetta...but only because she's dumb and didn't leave her ballista as Claude's army rolled in. I also beat Hubert and the foreign girl whose name escapes me, both of whom escaped rather than died. I attempted to "spare" Lysithea by beating her with the MC...but it looked like a real death scene and so I got paranoid and divine pulsed to only beat Claude. Maybe it just a misdirection but I didn't want to risk redoing the stage to find out.
That's good I can keep them alive if I want to...though I'm curious if there was a way to spare Ferdinand and Ignatz in the previous stage, since the requirement was to beat all enemy commanders and it didn't seem like they reacted to the MC beating them. When I do Edelgard's route I'll just brace myself for killing the house leaders and their besties though...and whoever else the game takes away from me.
NNID: Zephyr25 / PSN: Zephyr--25 / Switch: SW-4450-3680-7334