First advice: If your data is so “delicate” then make yourself responsible to back it up instead of leaving it on a single device expecting for it not to fail any time soon, RAID just adds fault tolerance for drive failure, it’s not a backup.
1- only if one drive is bad, if 2 drives or the controller are bad then the data is gone.
2- Windows 7 won’t see a SS drive because it’s formatted as EXT3, a Linux file system not supported by Windows.
Your chance is to take each drive out one at a time, run WD’s DLG to run a FULL TEST on each drive until you find the one that’s bad, and then zero out that drive with DLG. If all drives are good on the test then zero any random drive, just remember to put the drives in the exact same slot they were.