HTWingNut

From comments: https://github.com/openzfs/zfs/pull/15022#issuecomment-1802428899

"This feature will be available in the OpenZFS 2.3 release, which is probably about a year out."

Dated Nov 8, 2023

So still needs some time to cook.

SMART Stats?

It's like buying a car and asking "did a get a good deal" without stating anything about the car.

If a second data drive dies during the "snapraid fix" operation for the first failed drive, will the fix for the first failed drive continue without issue?

If a fix operation started and a disk failed, it will fail out and you will have to start over and fix both disks.

Similarly, if one of the two parity drives fails during a sync operation, will the second parity drive allow the operation to complete successfully without any interaction from the user?

No. It will fail out and you will have to rebuild the new parity.

If a fix operation started and a disk failed, it will fail out and you will have to start over.

The warranty is only as good as the company offering it. In this case it would be offered by the seller, Evrymm, which sounds like one of those generic Chinese spam selling accounts. You may actually get the disk, but I wouldn't count on getting a replacement under any kind of warranty except for the 90 day Amazon one.

They're using Linux...