A lot of questions here. No way I can answer them all, but here are some quick answers.
NetBackup and Networker are completely different from SnapVault. Those applications run within the Host operating system (Windows/Linux/UNIX) and back-up individual files by reading the filesystem that resides on top of the NetApp LUN. They typically send the backed-up files over the TCP/IP network to some sort of backup target (tape/VTL/appliance). The key advantage is that they can easily do single-file restores. The disadvantages are many: inefficient, expensive, complex, can't easily meet backup windows, can't meet RPO/RTO requirements, etc...
Based on what you're looking for, it sounds like Open Systems SnapVault (OSSV) is the answer. OSSV is a client you install on the Host operating system. It behaves similar to NetBackup/Network in that it backs-up at the file system level. That is where the similarities end. OSSV is block-incremental, not file-incremental. OSSV uses volume shadow copy to take its backups on Windows platforms. OSSV has native MS SQL integration so you can back it up in a consistent state. OSSV is extremely space efficient and it uses a NetApp storage system as the backup target. You can use OSSV with OnCommand's Protection Manager software (for 7-mode systems only). Last, but not least, OSSV is 100% free. You can deploy as many OSSV clients as you want at no cost.
NOTE: If you've read this post and feel the burning need to argue in-defense of traditional backup software, please direct your comments to the nearest brick wall. Thank you.
In order to take consistent Snapshot, SnapDrive needs to talk to controller that why it needs. The OCUM stored password of the controllers is not used. The same is only used for Backup filers and not the primary.