I could see them tear down the Garden Rooms for sure. The only question is whether there is competent soil beneath those buildings, or bedrock at a reasonable depth, adequate to bear the weight of a matching BLT South tower. I don't see the upside to replacing the existing bungalow-style buildings with new, like-sized two or three story buildings. Plus, I like symmetry.
I think they are screwed with the convention center. Its location puts anything taking its place that's over two stories blocking out both the iconic view of the Contemporary from Seven Seas Lagoon, and conversely blocking views of the lagoon from all or part of the existing Contemporary Hotel A-Frame. Build a new tower where the Garden Rooms are, and convert the convention center to parking to mirror the existing BLT lot at the north end of the property.