I did some research and found the following.
Disney is assessed for five "parcels" in the area. Two of the five assessed parcels are for the improved properties east of A1A. The "timeshare" portion of the site and the "hotel" portion of the site are assessed separately. This was done on purpose, no doubt, to separate the tax assessment for members from DVD's remaining share.
There are three other land parcels owned by Disney in addition to the previous two building parcels. Two of these remaining three land parcels are west of A1A. Parcel ....000.1 is 32.57 acres and this is essentially the lake. Parcel ....000.2 is 7.3 acres and includes the tennis courts and support building.
The third land parcel is vacant property east of A1A and south of the resort. This is the parcel that is the subject of the news article. The Appraiser's office lists this parcel as 9.16 acres. There is a small triangular parcel north of Sea Oaks that is owned by Sea Oaks. My guess is that this piece is being sold to the developer as well to make the total proposed project equal 10.41 acres. The small Sea Oaks parcel is landlocked with little value to Sea Oaks but lots of value to the new developer. The number of dwelling units per acre on this site would be just shy of 9. This is not unusual for low density multi family developments.
Long story short, it does not appear that Disney is selling any property for this development west of A1A and is only selling the property south of the resort. However, because Disney Vacation Development platted the large 32 acre lake parcel separate from the resort amenities that are also west of A1A, this could easily be sold. If that happened, because Disney owns all the frontage on A1A, this new development would would only have driveway access to County Route 510.
Lastly, although the newspaper said the property is sold, this is probably not yet the case. Most property sales like this are contingent on the new developer getting preliminary site plan approval from the County. If the County does not approve their development plans (and it might not based upon the complaints about size from the neighbors), then the developer either moves forward with a project of reduced scale or the property sale does not proceed and Disney would continue to own the property. The final number of units will depend on how much land can be developed and the zoning of that land.
Tax parcel information can be found at the Indian River County Appraisers web site.
http://www.ircpa.org
Jeff