If you copy your ED install to a different folder prior to installing DKS, you can go into your windows registry and check the registry setting for the game, write that down, then after install, add a new registry key with those settings pointed to wherever you copied your folder, I had to rename mine, I made it Divinity II - FoV just so I could keep them separate in my head, and launch the game that way. Doing that will allow you to play both ED and the new version, if you get your ED saves all the way to the end, they should import into FoV just fine I think, though I've not actually tested it that way. FoV saves of course work in DKS as that content is the same in both games.

Reality is but a shadow of one's imagination, is it not?