Bandetto

First, I would uninstall that iCUE piece of junk, go back to the older version like 3.38.61 (the version I run), not only that it is a lot faster but it is actually more stable. My experience with the latest iCUE was so bad that I was unable to use it. Seriously, consider going back to the old version.
 
In terms of the RAM issue, I actually have almost the same issue.

 
My RAM is inaccessible and unable to be used, I have my colours solid red so I didn't notice that they become frozen like is shown in the video, my best attempt to fix this kind of issue would probably be to ensure that iCUE is fully uninstalled, reseat the RAM slots, reinstall iCUE and force a firmware update and then restart. Let me know on how this works.
 
Edit:
Also, you don't even need iCUE to run the devices, if all you care about is just the fancy lighting, you can set it all up and when you're done, you can just remove iCUE and it should remember it's profile (provided you don't to advanced complicated stuff).

Going from 918+ to 920+ won't really be worth it. I still think however, that Synology makes the best "plug and play" NAS solutions. I suggest something more high end, like a 1621+ and then keep your 918+ for backups and maybe offload some processes to it as well. 

Your selection is fine, although I am not familiar with AMD, I think you may need to use a 2nd gen Ryzen to upgrade the BIOS of the mobo if it isn't the latest BIOS already. 
Also the entire selection is mixed brands which is fine but more stuff you need to install, like the PSU and fans, they are 2 different drivers which will need 2 softwares to run the RGB lights, also that PSU looks horrible, if you are getting a Corsair fan, I recommend going all Corsair RAM, fans and PSU. Far more efficient.

Whenever I want to get CPU models for a generation, I search "list of Skylake CPUs" or whatever generation I want, like haswell or Sandy bridge. According to Wikipedia:
https://en.m.wikipedia.org/wiki/Skylake_(microarchitecture)
CELERON G3900 models are the cheapest (or at least lowest end) made. Still, see if a local computer shop or repair shop can spot you a loaner, for cheap or maybe free.

Personally, after I made my own build and I installed everything, I stress test it to ensure everything is at it's perfect order.

Personally, after I made my own build and I installed everything, I stress test it to ensure everything is at it's perfect order.

I'd guess, but it isn't a stress testing software but a benchmark software. Here is some of the stress testing programs I use.
https://www.passmark.com/products/burnintest/
That's it.

Hey!
My name is Hamtaro and I have been watching LTT for a really long time, I just signed up for the forum and I can't wait to talk with you guys and gals