As far as we know the mainland of Morrowind was spared the fate of Vvardenfell and that it was the seat of House Dres witch was infamous for slavery. Now the Argonians did drive the Dunmer out of Morrowind and into Solstheim but is it that much of a stretch to see House Dres be flung as far as Skyrim? That and the only reason most of Morrowind gave up the slave trade was because of the empire. With the empires influence waning i don't think things look to well for our furry (and scaly) friends.
Destroyed, utterly.
If there are any Dres nobles left, they were running for their lives from their previous slaves and their Argonian liberators/rebels. They wouldn't have had time to take their slaves with them, and would likely have had a very difficult time keeping control of them with all that going on.
The most likely Dunmer nobles to survive would have first been Hlaalu, already abiding by the Empires laws and accepting outsiders, next Telvanni(if anyone figures a way out to live through that mess, they would have) and finally Redoran, who probably would have been the most likely to have territory close to Solstheim. Dres and Indoril on the other hand, being the smallest and/or the Weakest, dependent on their position in society(Indoril's control of the Temple) and location(Dres's control of the agriculture), the ones that abused the beasts the most and closest to them, means that this disaster would have left them in utter shambles if they even survived at all. The few that might have, are those that have managed to accept the changes and adapt to their new situation.
The Dunmer cannot afford to keep slaves anymore, they have enough trouble just trying to survive right now.