FanimeCon gets special convention pricing, so don't bother calling the hotels directly yet. Usually, the hotels have large blocks of rooms already reserved for the convention that will be provisioned through the website and company that specifically handles FanimeCon hotels. That would explain the lack of rooms. Also, if you call them, they will quote you their default rate, which is usually very high.
For the future, you should just wait for FanimeCon to announce official rooms if you want to reserve. In the past, it's run between $80 and $120 per night, depending on the hotel and occupancy, but again that is in the past and may not be correct for the future.
Also, PLEASE don't over occupy rooms. It can really piss of the hotel, get you into serious trouble (possibly get thrown out) and gives FanimeCon a bad name.
For the future, you should just wait for FanimeCon to announce official rooms if you want to reserve. In the past, it's run between $80 and $120 per night, depending on the hotel and occupancy, but again that is in the past and may not be correct for the future.
Also, PLEASE don't over occupy rooms. It can really piss of the hotel, get you into serious trouble (possibly get thrown out) and gives FanimeCon a bad name.