PBS67 wrote:
2. Clone drives to preserve state of original NAS drives. Is it best to clone the drives using something like AOMEI Backer Upper or transfer disk images to the new disks?
Actually, a program like ddrescue is better since it can handle bad sectors should the issue arise. However, if the drives are fully healthy AOMEI should be fine just so long as you get a full sector clone. It really makes no difference whether you use images or physical disks as long as you're getting full clones.
PBS67 wrote:
should I boot it in Linux with Hiren's Boot CD or what so that it recognizes the Linux MD RAID? Or; can I avoid the whole Linux issue and mount theses drives in WIN 7?
I wouldn't use Hiren's I'd probably use something more like Knoppix, Debian, Parrot, etc. to boot the computer. You can't mount the RAID in Windows per se, but there are data recovery programs such as Recovery Exporer and R-Studio that can read the Linux RAID metadata and automatically assemble it in the software.
PBS67 wrote:
4 Once the drives are mounted, is it a straight forward matter of running PhotoRec on the four drives? Or because they are no longer in the NAS do I have to take extra steps before PhotoRec recognizes that the four drives are part of a RAID 5 Ext 4 setup?
Most likely Linux will automatically assemble the four drives and give you a mounted volume to browse. You won't be scanning the four drives individually you'd be scanning the assembled RAID volume.
I personally wouldn't use photorec at all. There are programs out there for $70-80 that can get you far better results. Since you're not a Linux user, this is probably your best bet since it'd also enable you to do this in Windows which you're familiar with. Give demos of Recovery Explorer and/or R-Studio a try and see if it's worth the purchase.
Just be sure that if you do mount the drives in Windows you don't Initialize or Format the disks. This will seriously complicate recovery for you.