Update here on pump noise. I finally got around to switching my PWM pump from using the water pump header on my motherboard to using a PWM chassis fan header.
On the water pump header the pump was running at over 4000 (reported in the BIOS) all the time. Although still not overly loud, it was a frequency that was very annoying. Needless to say not what I wanted from my liquid cooled, planned to be quiet, build. Regardless of what settings I tried, at least in ASUS AI Suite, I could not get it to run the pump slower or in any PWM way off that header.
However, on the chassis fan header I have been able to create profile that allows me to run the pump as I would have expected. The result is at idle, running between 20%, the pump is dead silent. It's heavenly!
And even under load with the pump ramping up to 50% at 70C it is still a much more pleasing frequency, quiet, and has very little impact on the overall cooling. It is worse than running full out, but under load temps still stay between 70-80C.
I haven't switched my top fans to be intake rather than exhaust. I may do that but getting a screwdriver in to get those fans out with the loop now in place is no small feat.