on HP MSL204, robotic controller usually can be assigned to a tape drive. It can be done through the library console. When you connect/zone to that drive, host will see both robotic and drive.
if direct connection to NetApp filer will be your choice, you have to zone all drives to any NetApp initiator, as best practice, distribute both drives to different NetApp nodes as redundancy. as zone, you can use one initiator (NetApp) and one target (tape drive) in one zone.
after compare with the direct connection and remote connection. we use tape library connect to Netbackup server, then remotely backing up the data from NetApp with NDMP. in this case, the tape library can be also shared with different backup jobs on NetBackup.
Hope i answered your questions.