Mantic has put a video out. It announces an October release, as “The time of the Voidwalkers draws near”.
Screenshots of new art:
Also two new models (Credit Boss_Salvage).
Looks like soulflayer mounts are how commanders get around; maybe some cavalry?
Flying monster looks like a gordrake from Armada.
Not sure about the boats, but the void mutated elf looks cool (more sensible armour/attire would be nice though). The mutalisk looking things in the background ring a bell, presumably a new flying unit? Maybe stretched out Void Lurkers?
Looks like butchers and reapers on the right of picture 4; so straight nightstalker units are likely.