Depending on what you use your server for, backup/restore across a 1Mbit/sec uplink may be a non-starter in practical terms - it's just not fast enough.
Of course if you can do the primary sync locally and your dataset changes very little (so you only need to back up small amounts of data), and...
There are plenty of options - it all depends what features you deem to be most important.
If growing the array by one or two disks at a time is an important feature for you, and you don't want raid10, then ZFS may not be the best choice.
You can grow ZFS, but there are restrictions in how...
What performance figures do you get without the ZIL SSD?
With large sequential I/O, you may find sync writes are just as quick (or slow depending on your viewpoint) without a separate ZIL log device.
Issues like this can be caused by the disk, controller, psu and/or cabling.
If your other pools are functioning OK, then there's a good probability that the PSU is OK (though you can confirm this when you switch the cabling round)
Start at the basics, and do one thing at a time only
Switch...
In my experience, hot-plug and hot-swap are not quite the same thing - though I suppose it's semantics at the end of the day.
Hot-swap (as many LSI raid controllers support) literally means pull one disk out (amber light lit or not), insert another and walk away - the array takes all...
To be fair, the advice to go ZFS was certainly reasonable given the information in the original post - however the goalposts were later moved when "provide something that monkey-brained techs can walk into the server room at another site, see an amber light and pop in a new disk that rebuilds...
It's really a toss up between options 1 + 3, IMHO!
Option 1 can survive any two disk failure, whereas option 3 can only survive some two disk failures.
Madrebel's suggestion of 2x 3-disk mirrors can survive any two disk failure, and some 3/4-disk failures, but has the highest capacity cost -...
Personally I wouldn't bother with FCoE in the home - if you really need 10g speeds I'd look at 10g ethernet using copper CatX cable.
As to dedicated ZIL devices and L2ARCs, be sure you actually need them first before jumping in - you can always add them later if you need to.
Finally, your...
You could take a look at Snapraid - it's an application you run to provide raid style protection, but you can implement it with your current data - plus the latest versions have a pooling feature so that all your data drives can be made to appear as one - best of all it's free - all you need to...
Snapraid is fine on Linux - Ubuntu or Mint are probably the easiest as they have a repository!
Windows is always an option too of course, though personally I'd only repurpose an existing OS - I wouldn't pay money for an OS when Linux can do what you want as well or better, for free!
Strictly speaking DXVA is not required as long as your CPU can cope with all the decoding duties and a Core2Duo should (I assume you mean Core2) - however the CPU is a general purpose computing unit processor and will consume a lot more power during decoding than the dedicated DXVA decoder on...
Depending on your motherboard's options, you may be able to save some power by underclocking the CPU (perhaps even undervolting too) - though this needs proper testing to make sure you don't go too low.
The arrays you are looking at are designed for enterprise/DC deployment - they don't much care about how much noise they generate, but I suspect that in the your theater room this might be an issue for you - so I'd check around on that front first! I've no idea how noisy these particular arrays...