Harmy’s work is basically a re-mix, re-mixes are considered fair use. https://boingboing.net/2013/04/26/fair-use-decision-remixing-is.html
I do not think that’s the case, not under US law anyway. There’s a lot more to a movie than just editing it, and everything automatically copyrighted as soon as it is created, and that includes all the individual shots, the sound effects created, etc. You would only have a fair-use case if you can show that your creation does not impede on the market of the original, and there you have a problem because the DE is a direct replacement for the official release.
If Harmy did have a copyright on the DE then he would still need to make a proper license to enforce, simply saying not to sell it isn’t enough. Have a look at the Carol Highsmith case, she tried to sue Getty for selling her photographs, Getty had the case thrown out of court on the basis that they don’t need a license to sell works in the public domain. Copyright Attorney Leonard French pointed out that if she didn’t want people commercialising her works she needed to make a license specifying that.