Here is how I've always played, since ROTR: on the final turn, regardless of why its the final turn, the active character must be able to complete his or her turn as normal. This means if you can't draw up to full, you die a heroic (or tragic) death. But that only matters for the active player. Any of the other players who would be in a position to die next time they have a turn are spared, as the game ends before they would go. So the active character still has to be careful in the final battle, but everyone else can go for broke.
To save characters that will unavoidably die in a future turn, I allow the group to concede the game immediately (and only) between character turns. If a character does anything to start their turn (flips blessing deck, moves, etc.) then they must finish their complete turn before a concession can take place.
Mike, is this how it should be working?