The Cygor exists, its the Beastmen's only "war machine". The Ghorgon and Jabberslythe do not, nor is the Giant available.
A lot will depend on how what can fill the roles they feel represent the Lizardmen.
Tier 1 infantry will be easy between Skink Cohorts and Skirmishers. You get a block unit and a missile unit to work with. Tier 2 Infantry will be Saurus Warriors and Cohorts with Shields and/or Spears. And so on.
The question is what will they use as AP Infantry, will Saurus get Great Swords, will that be left to Temple Guard, or will Kroxigors do the role as well? Will the Bastilidon be their big heavy, or will we see different Stegadon variants? Will Ripperdactyls make it, or subsumed under the Terradons role?
Almost guaranteed, though, that Cold One Cavalry will be the Armoured Cavalry of the Lizardmen. Ripperdactyls are too light for that role (even with AP). We may see a new Monstrous Cavalry unit from them which use Monstrous Cold Ones or mini-Carnosaurs (I wouldn't say no to that), or we may see the Troglodon take on that role.
Mounts for the Lords and Heroes are level upgrades, which are selected much like their own traits. It would be interesting to see if they put the Engine of the Gods in that spot for Skink Priests or just have them be their own unique unit. Not having researched or played the Vampires, it could be similar how they do those Thrones of theirs...