Well continued from the earlier post.
And as for order? Well they've never needed a reason to be somewhere other then just to foil those dastardly Destros and their naughty ways (LoTD I'm looking at you and your soul casket) but beyond that as everyone should surely know: Mysterious Uncurable Disease cramping your style? Your need a cure! Wheres the incredible rare ingredients needed for said cure? In the Jungle. It's always in the freaking Jungle. So an Imperial Expedition Sets out for Lustria, they need to make up for lost time and so call upon the Dwarfs to provide Steam-powered ships to catch up. The High Elves, relatively sheltered from the Red Plague by their isolation in Ulthuan, were instrumental in ending the first Daemon War and since have always had High Lore Masters watching for signs that the Daemons might again renew their assault in the New World and so sail from their island home joining the Steam Fleet bearing the Rest of the Order Alliance to the new world.
So that brings pretty much every one over to the Lizardmen's backyard but would they come out to play nice with their potential allies?
The Slaan would be well aware of the Elves efforts in the first war but are from a lore point of view incredible insular. They do however follow the Plan of the Old Ones, foretold in Glyph Porphercies left by the Old Ones.
The various city states are all led by different Slaan Priests and are distinct in their own ways. Having a particular Pyramid City (Found suspiciously close to the searched for Cure and a key Geomantic node) that has been studying the time of the Red Plague and is aware of it's "destiny" to throw back the forces of Destruction is not too much of a stretch. Having the whole Red Plague omened by a sign maybe a streaking red comet across the night sky, gives the Lizardmen plenty of time to acknowledge the time is now and to raise a new spawning - the Red Spawning marked by the Comet Glyph. (I'm waffling a bit here, they had Spawning last edition I played, meant they were destined to be certain thing no idea if that's still cannon or not.) A new spawn fit to meet new or rather old threat in head on, flexible enough to accommodate new ways of thinking and without with prejudices of older reptiles.
With Orders arrival being pre-ordained and not there to loot relics (the main reason Lizardmen go to war with the good forces in warhammer) there's no reason why a alliance between the Slaan Mage-Priest of the city and the High Elves lore masters could not be agreed.
So that I think would be not be too blasphemous against the existing lore, indeed within the spirit of the IP. Course it wouldn't explain why the Lizardmen would be running round Praag taking keeps, but I think they would follow their Allies back to the Old World should their plan tell them to. If not, they've been known to invade Naggaroth over looted temple relics, theres no reason if something particularly important was spirited back to the old world they wouldn't follow it back as well. I'm thinking perhaps the same Macguffin that the Dark Elves are so interested in.
Well it's not perfect by any stretch but then neither is Dwarf and High Elves buddying up to the extent they have from a Lore Point of view. I think it would pass the muster but like I said by IP lore is rusty, what do others think? Could it work?