As for the NR200, NH-C14S is one of the better options with a 140mm fan on the side bracket feeding fresh air for the CPU Cooler.
As for tower coolers, either the NH-U12A (now in sweet black chromax) or the Scythe Fuma 2 will perform well. Typically, intaking fresh air from the rear will yield a couple of degrees difference, at the cost of more dust (as the stock NR200 doesn't come with dust filters for the rear, but one can just buy dust filters and magnetic strips to diy).
Bottom GPU fans wise, the jury is still out though. Typically, in my experience, bottom fans will help the temperatures during idle or low loads. At high/max GPU loads, they don't make much (if any) difference.
And yub, Machines and More has done a lot of videos on the NR200 too.
Personally, I run a Thermalright PA120 Black with 3 Noctua NF-F12 ippcs in my NR200, running rear intake to cool a 5800X. And it does it job well, but I am not the best judge of noise, as at full tilt of 2000 rpm, the fans scream and it's tolerable as my standing fan next to me is equally loud.
Can't comment on the NCase or U9S though, as I don't own either!
