^^^
Having lived in Santa Clara in the '80s, I was there for all the fun of what to do with Great America when Marriott wanted to close it (remember Marriott? They developed the two Great Americas as twins originally). At the the time, Santa Clara decided they wanted to keep the park open and used eminent domain (I think) to buy the property from Marriott. My recollection of all the details may be a little fuzzy but IIRC, they hired Kings Entertainemnt (King's Island, King's Dominion) to run the park. A few years later, they leased the park to Kings (probably for 50 years - the 2039 lease expiration would make that 1989 which sounds about right) which was swallowed by Paramount and then sold to CF.
As to the question "why would CF have to give them the option to redevelop their own land", the answer is because it's leased to CF as the successor to Kings as the holder of the lease. Generally, when real estate is leased to another party, that party has the right to have the property as is for the term of the lease. Even though Santa Clara owns the property, they do not have the right to modify the property due to the lease to CF.
My take is that this is negotiation through press release. It sounds like the city wants CF to relinquish the lease (or part of the lease) on the parking lot and CF is saying buy out everything (park and parking lot) or nothing.
BTW, if you search for stories about this, you'll find references to "Santa Clara County Assessor Larry Stone". That's not me, I've never met him, but I certainly got plenty of phone calls for him when I lived there.