Best answer by cbrown
You would create 2 remote containers in LA (one for NY, one for Miami) and LA should be licensed with Ultimate (http://www.nutanix.com/products/software-editions/) to get the many-to-one feature. The other sites can be licensed at any level. You'd then setup the vstore mappings on the each site to their unique container.
Snapshots are stored in the .snapshot directory on the container. The space they use is variable, but it depends heavily on the size of the VMs you're protecting, the rate of change of those VMs, and the number of snapshots you retain (and any data-reduction tech you're using such as compression/EC-X)