You do not need to export SIS modules or their containing areas. SIS modules and areas are exported as a part of the SIS Network subsystem.
As a result of the above steps you should have one export file for the SIS Network subsystem.
Exporting the entire SIS Network is the recommended method. You can export and import SIS Network Domains, but if you have System Global Secure Parameters you must be careful. If the configuration is not stable, exporting and importing domains may cause System Global Publishers to move between slots which changes the CRCs.