As far as I know there have only been a couple legal kerfuffles with fan edits, and they’ve been sites that hosted them and nothing more than cease and desists.

As for downloading and watching a fan edit? As far as I know no one has ever gotten in trouble for that and I doubt anyone ever will, honestly (barring some drastic changes).

The people who get in real trouble for this sort of thing are just the people who rip movies (or worse - leak) and just upload them as is on the internet in large numbers. Off the top of my head though, in terms of the people downloading the stuff, I don’t know if anyone’s ever been punished worse than a fine (and again, this is in regards to plain old piracy).

Bottom line: don’t worry. You’ll be perfectly fine.