Oh, I am not a settler, I was born in Sevastopol and lived here most of my life, as most people I know. It is hard to be sure, but I'd say, only about 10% of the current population came after 2014, the rest lived here before and then took Russian citizenship.
Cancelling property deals after 2014 would effectively mean most will still be able to live in their homes and apartments but will never be able to sell anything. It took me 5 years to change Ukrainian documents to Russian documents (property documents, passports, driver license, everything), and I still have not received and will probably never receive ownership on the small workshop that belonged to my father's company because it requires something from Ukrainian archives, which is pretty much impossible to obtain. I spent months of my life standing in queues in government agencies and in the court. I cannot imagine changing everything back, it will take decades!
And then, what about the kids who were born here after 2014 and have no Ukrainian documents? What about tens of thousands who lived here all their life but who always were Russian citizens, like my father in law? Sevastopol has been a Russian navy base since 1783, there are so many people who are kids and grandkids of retired navy officers, who were born and lived here but never had Ukrainian citizenship. What about their families, and everybody who had some relation with Russian navy? Half of guys my class in 1994 went to the local Russian navy academy and became Russian navy officers, no chance they or their families can re-integrate in Ukraine. And then the Russian military shipyards, and the local branch of Moscow State University and many many other Russian institutions which were functioning here since forever and all the people working for them and their families... Russia has always had so much presence here, I honestly cannot imagine Ukraine taking over Crimea without expelling or imprisoning half of the population.
Sorry for the brain dump, I didn't mean to make a statement or prove anything, it is just such a mess it hurts to even think about this all.