Q1 sorry no experience, but i would buy nano coating! I think you will still have some pump noise...
Q4 I use Open hardware monitor, gives me CPU and GPU temps....but I dont use them as imput variables..only for reference. The AQ5 is self contained..keeping it simple..I use it's hardware inputs
Q5 inline liquid temperature sensors
i prefer in and out of radiator(ie 2 sensors), but placement of sensors somewhat of a topic on forum. And Ambient air , case, Vregs (2) ( think AQ5 comes with 4 sensors)
Q6 all pumps are best decoupled from chasis, I used
for pump and am very happy with result
You will have to decide what tube diameter you are going to use, really not a lot of difference between 3/8 and 1/2"
How many fittings...you need to grab pen and paper and draw your loop, avoid 90 Deg elbows and go for 45 Deg, remember modern tubing can bend.
I used compression fittings as they don't leak.
Q7 I think yes if they are something like 10KOhm some one else maybe able to confirm resistance
Q8 AQ5 rated at 12W / channel with air cooling, I am guessing 20W water cooled, I went water cooled...it's a water cooled computer

Q9 apparently you can, so you can control 3 light arrays
Q10 sadly no experience ( my loop predates them) but I recall this being answered on this forum. certain situations not needed, but I would fit one, and no they are not supposed to leak.
The AQ5 Lt mmm

given your investment, grab a pro! I have Pro and am very happy with choice
Have the Koolance 370 and koolance GPU block for my 7970... to do it again I would go for a high flow EK for CPU.
hope that helps