The Hatbox Ghost's issue was that Imagineering has wanted to do it since the projection mapping effect rendered it possible, around a decade ago. Disney just spent a good deal of money on the Constance scene, and were not interested in spending more money plussing the mansion until TDA started searching for the cheapest options to offer for the 60th for both tourists and locals. Be thankful that Walt opened the park in 1955, that's seriously the only reason why HBG is in the Mansion right now.
The golf course is so on another level of impossibility that it doesn't come down to the sheer fact that the land isn't bought yet. If it wasn't an extreme hassle, or the buyers were even WILLING to sell, then Comcast would have bought it in a heartbeat. Seriously, they would've. Do you see what they're doing in Orlando? They're literally using almost every inch of space they got at this point and the plans are so wild beyond that. There is nearly no limit to how far Comcast will go, but only to what they possibly can. They just ain't selling and it ain't happening anytime soon.
The studio will be fully gone before that golf course is sold to USH, I'm tellin ya.