If initiators within an initiator group has an IP addresses associated with it, does that mean the initiator IQN can only be allowed to mount the volumes from that IP address? And if one does not have an IP address associated with it, will it accept the IQN from an IP address?
To gain access to a volume the initiator must match both the IQN and the IP address if it was provided. If you use * for the IQN or IP unrestricted initiator connections will be allowed. So yes, and yes if you use *.