The static listener is needed for the RMAN connection later. Since there is no database to connect to RMAN uses it.
1)Why do we need to use the static listener?
The problem is I cannot find a quote where "Broker" is not in the picture.
At this point there are two similarly configured but different Oracle RAC databases, each in the primary role. Before creating the standby database, update the network configuration files on all systems to ensure proper client access to both databases and to create the static service entries used by the Oracle Data Guard observer and broker command line utility, DGMGRL.