If you look at the maps of the district land holdings you’ll see that there is a small amount that runs along the district’s border creating a buffer. That reduced the amount of property within the 300’ zone.
Even if they did need to send notice to these neighboring parties, they still need some harm for standing. Most zoning disputes arise out of changes, not maintaining the status quo. So the district needs to find an affected land owner who feels they would be harmed by things remaining as they were for over a decade. And since the Comprehensive Plan is relatively new, that they didn’t object during that public process throws the sincerity of their concerns in doubt. This whole ordeal has also now been even more publicized and they still haven’t come forward. That’s a unicorn they’re searching for, an adjacent property owner who in the past year realized that the status quo is a potential harm, has missed the national news coverage but definitely would have responded promptly to a mailed notice. They needed somewhere there today taking about how Walt Disney World still being Walt Disney World was going to be a harm to them as an adjacent landowner.
There’s also the possibility that the existing agreements and covenants with the other land owners in the district limit their being affected.
Last, there is still the original charter and its rules regarding the conduct of the Board of Supervisors.