I think the issue might be that
@letsgobirds is using points and I've seen Marriott limit the number of rooms it will allow for a points booking. However I think the advice to contact Marriott CS is a smart move. Also, like with Disney, if you don't get the answer you want you can try calling back and getting a different person!
On the positive side, though, I think November is a pretty safe bet for the Swan Reserve to be open. I was at the Swan last week and it looks pretty close to being done. My bet would be that it will open early to mid October.