You would not want to view the video on your EIZO through the GPU instead you want to use a Blackmagic Decklink card or something similar.
I would definitely opt for an X99 based board and completely avoid a mini ITX motherboard.
A Quadro is a waste of money for video work as you want to avoid the GPU to display your video.
Also the output of the power supply is on the low side.
3200 memory is complete overkill in my opinion especially if you want to overclock your CPU because raising the memory speed actually reduces the overclocking room for the CPU.
Here is some night footage of the Sigma 50-100mm on a Panasonic GX85 with IBIS using the Metabones Speedbooster Ultra for Canon mounts. Most scenes use an aperture of f/1.3 and ISO 1000.
"Full name, Date of birth, Identity document (passport, identity card, etc.)
Address and phone number, Email, Photography for the document (digitalized)"
Jeez, one would wonder why they don't ask for the social security number and a fingerprint as well. This is absurd!
For 5K I would definitely opt for a X99 chipset.
>> "At the time (fall 2016) there is no cinema that uses a higher resolution than 1080p (or 2K at maximum) for digital projection. "
I think you are completely wrong about that one! Since 2009 theaters have started to upgrade their projectors to 4K.