Is it possible to move a (Striped, 2-Drive, Safeguard enabled) SoftRAID from the two internal Mac Pro SATA bays to an external 2-Bay Thunderbolt 2 RAID enclosure?
Absolutely. SoftRAID does not care what bus a drive is on. only that it be reliable.
Absolutely. SoftRAID does not care what bus a drive is on. only that it be reliable.
I like the "reliable" caveat and completely agree.
Do you have any recommendations of USB-C/Thunderbolt-3 enclosures?
All enclosures for Thunderbay 3 must be "Certified".
Same with Thunderbolt 3 cables. They must pass a certification test.
USB C is a little different. It is up to the Manufacturer to certify their cables and enclosures and budget manufacturers may elect not to do so. There have been engineering reviews from USB cable testers demonstrating that inferior USB 3 cables can damage iPhones, Android phones, and other USB devices.
We expect the same is possible with non-certified USB C enclosures. Make sure that any enclosure you consider has passed certification. Stay with solid brand names that you can count on and will stand behind their offerings.
Consider how much data moves across Thunderbolt 3 and USB C:
A short USB C or Thunderbolt cable can hold many megabytes of raw data when files are being copied. That is just data "inside" the cable at any time! Quality is becoming more and more important.
It is worth the investment to buy quality. We have seen many low end enclosures that corrupt data over USB 3. I expect it will get worse with USB C. Every manufacturer should have a published web page that shows their devices have passed certification.

