GrandTotal has been developed from the ground up for collaborative work. Distributed work is possible without additional infrastructure.
In brief: The company file (Companyname.grandtotal) can be stored in a cloud drive like Dropbox, iCloud Drive or Google Drive and can be edited from different devices at the same time.
In detail: All about collaboration
In brief: It doesn't require more licenses than if you work at the office. However, on the home device one of the licenses must be activated.
In detail: All about the licenses