You have to include any and all considerations and agreements that Fox may have with LucasFilm . Disney doesn't get to call the shots in this.
I wonder what kind of distribution restrictions Lucas likely would have forced upon Fox. Certainly he knew one day he would either be dead or no longer in control of LucasFilm. Considering his nature, I think he would have been very through in controlling his creative content.
I think you're misunderstanding how licensing usually works. From a legal perspective, at this point, Lucas' wishes are irrelevant unless there's some term in the sales deal between Lucas and Disney (and even then, I'm not sure if it'd hold up in perpetuity). Lucas could put a clause into the Fox distro agreement saying "No releasing the OOT ever unless I say so" (e.g., the 2006 "bonus" discs), and that'd be all well and good, but the agreement is likely with the corporate entity that is LFL. So, the real question is whether LFL -- the corporate entity -- permits the release, assuming such a clause even exists (which I doubt it does).
Thing is, LFL no longer = George Lucas. He has, based on the stories I've read, totally divested himself of any control or interest in LFL. He doesn't own it, he doesn't manage it. It just has his name on it. That's it. Any contract negotiated between LFL and Fox can either be amended (e.g., if it has a clause saying "No release of the OOT EVER UNDER ANY CIRCUMSTANCES"), or the release of the OOT can be waived under the contract, or the release can simply proceed because the contract doesn't expressly prohibit it and merely CONDITIONS it on LFL's approval.
LFL = Disney now, for purposes of ultimate corporate control. Disney owns it 100%. If Disney says "Do XYZ" then LFL does XYZ. If Disney says "let Fox release the OOT" then any contract between LFL and Fox which would prevent that will no longer apply, George's wishes notwithstanding. George has no ability to prevent it anymore, from a legal perspective. He could disavow it, raise a stink about it, etc., but he can't legally stop it anymore like he could when he owned the company.
Kathleen Kennedy may be in charge of LFL and Disney may basically keep a hands-off approach to managing LFL, but if Disney wants LFL to do or not do something, then LFL will accede to Disney's wishes or Kathleen Kennedy will be out of a job, regardless of whatever she may have promised George.
Regardless, my bet is that the way the distro deal works is more that Fox gets a right to distribute whatever LFL produces for the old Star Wars stuff. So, in a practical sense, if Disney/LFL greenlights a remastering of the OOT for blu-ray release, then it goes to whatever remastering house to do that (say, Lowry again), and they remaster it. Then, per the terms of the distro agreement, that material must be given to Fox to put on discs, stick in packaging, and sent to stores. Fox gets its cut, and the rest goes back to Disney/LFL. That's it. That's the deal. Fox doesn't get to decide when it releases stuff because Fox doesn't own the content. Fox just gets a right to profit from distributing it when LFL decides to do another release. So, if Disney/LFL decides to do it, then it's happening.