I solved this problem by calling
queue_free() on the player when they die, but it depends on your set-up (if the camera is a child of the player, it will disappear too; death animations might not play if they're children of the player, etc).
You can disable input with
set_process_input(false), so one way to do it might be:
The timer you create with
yield(get_tree().create_timer(1.0), "timeout") would give you space to play the animation (make it as long as the animation), and then you can remove the player from the scene.
Hope this helps!