EVERYTHING published about why the delay is pure speculation. Not one thing said is any more credible than another. This particular reason makes the most sense. The AA should be done and ready. If they were reverting back to the way it was until recent Presidents there would be no reason to delay. If they were going to have him speak, it should be done and finished and no reason to delay. Scheduling shouldn't be a problem since there is ample time for golf, this only takes 20 minutes per previous reports. Disney has been doing this for years with no issues, so the issue is clearly coming from someone else. WHY would Disney say late 2017 if they had an agreement? Only makes sense if there is a great difference of opinion since nothing else really comes into play. Sadly this makes perfect sense. Disney's company, Disney's park, Disney's attraction. They need it done in a way that is Disney style and appropriate or change the process back to the original so this isn't a problem in the future.
PS Most of what is on this sub-forum is pure speculation and copy/paste from other sites, so this fits.