Only way this can work is if you have an toslink optical or an analog coaxial cable. I have the same setup minus the daughter board. Its a pretty cheap cable and you can get it at monoprice.
Coxial Cable...
https://www.youtube.com/watch?v=JZfK6YkU9_E its a review of the monitor I found. It does show some good angles of the monitor. Plus regular use and gaming use.
My parents have an aging computer full tower too. Definetly would love to upgrade them to something smaller and more discrete. Would totally use it for their anniversary. I want it lol!
Black5lion knows whats up! Ya even a cheap 750, way better than integrated graphics. But the ya your right on the processor, especially if its moving into a file server later on. the 1246 V3 would do great!
Not sure why you need a server grade processor. Your fine with core i5 I rather put that extra bit of money towards a gpu even a cheap one then upgrade later. As for 4k gaming, I think you might be able to squeeze in a AMD 295x2 that probably the best you can do in that size case. Should more...
Your Lian Li case will not work with a regular power supply, you'll have to buy an sfx power supply. There's two versions by Silverstone one is modular one is not.
8g should be fine but 16g is best if your are doing any video encoding or large photopshop files.
you can run 4k on...
I went from a note II to a 6+, it's a change for sure, but I love the 6+. Super simple to use, and battery life is superb! I'm a heavy user and I can go all day without needing to charge it.