Sorry for the losses. I've got at least another month or more before I can make any kind of decisions re; dead outs. They are always a bummer…. I agree though, trim any newspaper remaining outside the hive body when adding dry sugar above, its why I only use a piece of paper large enough to cover the center hole or holes depending on type of inner cover.
You're also right about the amount of moisture dry sugar collects. By the time the bees find it, if needed they're usually licking 'rock candy' instead of the granulated sugar I left them.