I'm not sure whether they own the land or not myself, but I can tell you some sort of land swap occurred. It was supposed to 10-12 years ago while I was playing RHCC as my high school course. Delays and the housing crash pushed the new course's construction back over and over.
I really don't know much about the new course, other than that a member I've talked to is excited for the range/short course and to have a course that can extend to 7,300 yards (the old Rolling Hills was about 6,100 so there's a bit of a complex with the membership, more than most even
).
I'm excited to see how it turns out - the bottom half of the holes in the diagram are along the same corridors as the original course. I'm concerned about the bottom 4 holes which occupy the same land as the old 1-3 and 18th. Those areas may still feel a bit cramped, but the rest of the course should have more room than the old course.