Mix Raid? bay arrangement for raid 10? different raids performance benchmarks?

Hi Professor_X,

Thank you so much for spending the time and effort to answer my previous questions.

It would be great if can have a look at the below link and tell us the reason for failing test1 in the article:

Was any action (firmware) taken to cover the above mentioned bad HDD detection failure?

I read a lot about Raid arrays and came across ZFS which seems to me a safer option as it covers the silent data corruption by providing data checksum to avoid any raid loophole which I have personally experienced before where the drive might look healthy and has no issues but the data is getting corrupted.
So, does PR4100 has a native ZFS solution?
I also saw this article in the forum: " [FIRMWARE] FreeNAS on PR4100 - updated! " which is showing a great capability to use FreeNAS on PR4100. Would this be the only way to enable ZFS/Raid-Z on the device?