As far as new death models go, we are getting one shadespire faction, which is not saying much given that bloodbound and stormcast alone are getting two each. Something has to be coming for deathrattle soon. I'm guessing that with the shadespire skeletons, a bunch of new deathrattle stuff is coming for our first AoS faction with new models.
Aye, it sounds more like the undead fleets in FB and Dreadfleet, but they definitely can be lead by vampires. It's funny that the idea was present long ago but only now, I hope, we will see such miniatures.