Correct, cliffracers were driven from Vvardenfell, not existence.
Also, I never understood why people dislike them so.
Dragons are more annoying, they arent as easily dispatched.
The fun I had just casting a weak levitate at them and seeing them plummet, or killing five in one go with a lightning bolt.
They were only a problem for level 1 characters, really.
As for any Vvardenfell creature being on Solstheim, there is this old fan-story that I love:
"Captain's Log of the Imperial Trader WandererSun's Rest year ...
We were coasting into the lee of Vvardenfell when my lookout awoke us all to the danger or we would have died today. This is what happened:
Lookout calls: "Ahoy there Capn - movement six points off the starboard bow - 2 miles distant and closing!"
I rushed to the bow and watched intently for some minutes through my spyglass as a vast, dark tide spread towards us accross the strangely calm sea from the not so distant coastline.
Then my mate Raffy, a sharp-eyed Bosmer, called out: "It's a white guar! He's leading them!"
And the nine bless me if that wasn't exactly what it was - straight out of the Tales of the Nerevarine my dunmer mother used to tell me - Saints preserves us.
I looked again and saw that the tide was made from every sort of creature you had ever heard of inhabiting that war-torn Island. And then all the hair on my head stood up as if in a great wind. There was a huge flash of light and several seconds later a monstrous report.
"ALL HANDS ON DECK!" I bellowed. "MAN THE LINES AND SET FULL SAIL, BE READY TO RIG FOR A BIG STORM! TIE DOWN OR JETTISON ANYTHING LOOSE, CHECK THE CARGO IS SECURE AND MR RAFFY, FOLLOW THAT WHITE GUAR!""