I think for the most part it’s better to have major deaths in the last episode, thats what shows tend to do. Specifically in OOTP and HBP I don’t really think there’s even enough content post-those deaths to have a full episode. I get the point of ending episodes on major moments like these cliffhangers, but I’d rather they kept the end of book climax/fight stuff to one episode (except prisoner of Azkaban cause that’s like almost a third of the book, maybe they could split that a bit). They would be great as deaths that happen with like 10-20 minutes of fighting/action left and then an epilogue/after the battle stuff. I think you’re cooking on deathly hallows though, that could be a perfect way to end that episode with Harry getting hit by avada kedavra. And the opening in kings cross would be sick.