If they do make Shirogane FC only when it first opens, I sincerely hope that they do not announce it before the servers go down. If people have time to prep beforehand then (even more than normal) people will have 1-person 'shell FCs' ready and waiting to swoop in and get houses for their private use, completely defeating the purpose.

That being said, that's a huge 'if' and I highly doubt they will make it FC only.