What made me post this is that it looks like you have severel drives fail at nearly the same time.
I don’t know if your problem is the same as I experienced with an early WD2002FYPS (same FW as yours) but I got the same problems running the drive in 2 (different make) enclosures (where I had/ and are using severel WD1002FBYS w/o problems) Failures also registered in SMART log (can’t remember which failures and don’t have drive online so I could look.
One of my enclosures : http://www.raidsonic.de/en/products/backplanes.php?we_objectID=5896
If I connected the drive directly to the RAID controller with only one SATA cable the problem seemed to be gone but I don’t trust the drive.
So I in my book some (?or all) of these drives are defective by design, problem maybe in the SATA interface IC area ?
Maybe fzabkar knows if there is more hw revisions of this drive ? ( I doubt there is ) so I would consider to replace the drives with another model (or make) RAID grade drive when you (I sure hope so) have gotten your files recovered.
So if you have important data here you should consider to take them to a specialist and not try to get them online yourself cause you risk destroying more files in the process.
Many times he can make some kind of track to track copy of the drive so work can be done on the “copydrives” in stead of risking to corrupt the original data (on the original drives) if one repair operation fails.
Also above if you don’t have same drive space elsewhere .
In my country there has come more companys in the harddisk repair business so prices has gone down so maybe you should get a quote before you spend maybe many ours trying to get your date back ?
The harddisk repair company could also maybe help you to get a refund/replacement (to another model:) ) on the old defective drives from WD.