User blog comment:Metadwarfosis/In anticipation of volume 11- Dwarven Kingdom and Expectations/@comment-72.20.138.102-20160817182214/@comment-29248623-20160817235402

To jump in on this: I believe the Dragon Lords have not been hinted to have any particular concern for dragons outside of the other dragon lords.

As for Aura and Shalltear, the other cover may simply be focused on the volume's highlight event. The covers from the other volumes are made just like that. Aura and Shalltear may simply be in some other part of the dwarven kingdom or were under orders to observe while Ainz shows off.