Also, keep in mind that they did own the land and likely had plans for it before. While there have been some parts of that area taken off the table and also not yet re-acquired, plans probably existed, which likely included at least general infrastructure which could likely be adapted to fit a lot of possible modifications fairly easily. Since they were involved in the site cleanup along with Lockheed they of course know the soil conditions, existing power/water/fiber runs, drainage (minus modifications for development that has and will be happening), the whole nine yards.
I would expect that if they make any kind of announcement on the use of that land by the end of the year, it will be after they have all of the remaining lots tied up with purchase agreements, at least behind the scenes, if not publicly on the books as theirs.