Agreed.. My first couple of PSUs were Corsairs... Sad to see where they've landed with respects to their standards. While the unit "did" pass, I wouldn't trust it and like Paul said, spend a couple of extra $$ and get something with more / better features.
I had the LG V10 and the software updates for it were horrid (with respects to timing). Went from the V10 straight to Pixel XL and haven't looked back. Went XL, to 3XL to 5 (There is no XL for 5 sadly).
I just made the move back in October, so I'll be good for another 2-3 years. Only...
From the sounds of it, you've already painted a picture of which option you're gonna go with. Can't afford #3 right now (or at least don't want to spend the extra $$ on it), and #1 is probably going to be overpowered by the estimated machine loads. Option 2 should be able to handle your...
I'm kinda jelly... Getting that for free is awesome!
If you've got the use for 10G, I'd go with Option 1 myself. $100 for onboard 10G network is a + instead of adding a Intel card..
Problem with doing a build guide right now is that NONE of the parts that are desirable are even AVAILABLE! The over-inflated market value on components makes one of these guides difficult to **** near useless to put together.