I'm amazed by the time and effort you put not only in building the PC but also constantly making updates to share your idea with us.
The LED-backlit acrylic panel is really innovative but In my opinion, the glow isn't even across (also a bit too bright). I would get a thicker panel (5mm) and have the LED strip on the side. Might cause some interference though so I don't know if this is actually doable.
Interesting tube routing, wouldn't it be easier to have just one tube connecting the CPU and GPU block?
Might be a good idea to add some dust filters for your 480 rad, it can hide behind your fan covers.
A clear blue coolant works better with your reservoir since it is LED lit.