Short of talking to either Gary Graver or Beatrice Welles-Smith's attorney, I don't know that you'll find any solid info about the legal problems of the film, which relate mainly to screening it, it would seem. What Graver told a group of us at the screening I attended was that every time she got wind of a screening he'd set up, Welles-Smith would have her shark send an injunction trying to halt it, as she has ownership of the film Othello, and could claim portions were being shown without her consent. Consequently, that's why you'll see things like listings for a "secret film" at the Seattle Film Festival or some such event a few years ago. The Germans who own Filming Othello haven't had any legal challenge I can imagine, as they are clearly the owners of it. If they ever tried to release it here in any video format, I'd imagine they'd run into problems then, as presumably Welles-Smith would have to be compensated for the use of her material. But I'm not a lawyer, so who knows. The documentary has had high profile screenings in the USA, so I don't know how those came off without problems.
I have some screen caps from my videotape copy I did for the site a while back, but they aren't of great quality, as the tape is not super-sharp, but I can post them here if you want.