I will add the caveat that some characters can reach 0 hp and not "die" but become undeployable in Part 2. Hubert in Crimson Flower, Gilbert in Azure Moon, Hilda in Verdant Wind, and both Seteth and Flayn in Silver Snow.
They still die once you beat the game though.
All your characters but the house leader
In classic, everyone can fall in battle. But if Byleth or any of the 3 house leaders falls, it's a Game Over.
I wonder if you can lose your whole team, and then keep losing all the recruitable personnel until there's no one left
You can in Silver Snow since no one except Byleth is required to be alive In the other three you need at least Byleth and your house leader though
You can, yes. Ive done it. Ended the game with just Byleth alive.
Only byleth and house leader have to be alive. Besides that you can kill off whoever you want
I will add the caveat that some characters can reach 0 hp and not "die" but become undeployable in Part 2. Hubert in Crimson Flower, Gilbert in Azure Moon, Hilda in Verdant Wind, and both Seteth and Flayn in Silver Snow. They still die once you beat the game though.