If you really are worried that Dawn will be the AD left standing, thus the National Sales Manager, send a very professional email to Joe outlining your position, pointing out the reasons why you believe H would be the better fit. Don't run her over, just emphasize H's qualities & experience that will give this limping dog a chance to survive.
We know with her it is over.
And look, you've got nothing to lose, if you're downsized you get a big going away present, if you leave on your own because D is your new bosses boss, you get kicked in the rear on the way out to your new job.