Here's my experience with a C14s
It you want to use the C14s and the stock fan you will need to use the Ncase ATX mounting bracket that turns the psu 90 degrees, and then a sfx adapter (not included). This gives pretty good cpu temps (full load was 73c or so on a non-delidded 8700k), but a really hot psu, especially my Silverstone 450 which was near meltdown and made the case look extremely full. Keep in mind this is with a 3/4 length RX 580, not a full length GPU which would limit air coming up from below even further. Switching to a Corsair SF 600 lowered psu temps to within reason but still left the case warm, quite full and difficult to work in. Note, the Corsair was quieter than the Silverstone, even when cool. Such a better psu.
If you plan to mount the psu flat against the side using the Ncase SFX mounting bracket with a C14s you will need to switch to a 120mm fan. This will raise temps on the cpu by about 10c but the PSU will run at pretty much room temp even under load, at least my 600 does and makes the case look a lot more roomy.
To fix the higher cpu temps I considered mounting a slim 120 over the c14s in the side panel sucking air out of the c14s and blowing out the side but I didn't have any on hand. Mounting a 120 on the forward spot on the side panel will work if it's slim but it blows air back into the cooler so it needs to be slid towards the front of the case by about an inch. Doing so eliminates the overlap with the cooler and even allows for a full height 120mm fan, I printed an adapter to make this work. It's still warmer than the stock Noctua 140mm fan, but I don't know if that's an air issue or because the cpu fan is just not as good as a Noctua, I suspect it's a combination of both. I may try rotating the psu again and putting a slim 92 or something in the side intead, it will be full but allow the cpu to run cooler and psu to run at low temps (I hope). I also kind of like the full look.
In the lower half I have dual thick 120mm fans in bottom blowing into the GPU (they barely clear) and 50% taller feet (18mm). I've never run it with the stock feet so I don't know if that matters but the GPU fans never come up to full speed due to the lower fans. I may cut out the lower grills, that will further reduce wind noise and eventually switch to Noctuas.
None of my current fans are Noctuas, I used what I had, but at idle with your head one and a half feet from the box you hear a very low whisper of air woosh but no real fan noise. Any other noise overpowers it, even my mouse sliding on the pad so I'd call it quiet. Under load you hear a hum from the box and a bit louder woosh but no actual fan noise (except for that one gpu fan that's dying).
Advice:
Ignore ram speed, just get good quality memory of reasonable speed. You just need to make sure it's not a bottleneck, after that it only matters in benchmarks.
I highly doubt a C1 is going to cut it with that cpu, it might, but only just (overkill is better). If you want simple, get a U9s with second fan. If you want better, get a C14s but be prepared to play with fans to find the right combination. Kraken works, but like the C14s, be prepared to play with fans and possibly even have to swap the GPU cooler and go down draft instead of updraft to keep everything cool and quiet, this requires an aftermarket cooler.
If you go aftermarket GPU cooler, make sure the Accelerro III fits, as you noted the 4 has some issues and will not work with a lot of CPU coolers due to the upper heatsink (such a bad design, no direct memory and vrm cooling) while the 3 is not listed to work with many newer GPUs. I've read the main heatsink on the 3 and 4 are identical, it's just the accessories that differ but I can't verify it. If true, and I suspect it is, you could buy a 4 and install aftermarket VRM and memory heatsinks like the 3 uses but that's assuming they are the same and you are willing to spend the money. For me it end up costing about as much as I spent on my GPU and not worth it.
While I'm sure the Kraken/Accelerro is going to be cooler under load, I'm not convinced it will be quieter, particularly at idle and close to you. It's also a heck of a lot more expensive. Then there is the system maintenance, you have to (carefully) work with the radiator hanging off and it's water cooled which comes with it's own risks. I'm not knocking watercooling, I considered that option and haven't ruled it out, it just comes with it's own issues. Not that it's a picnic working around a C14s, seriously, it's massive.
Everything in cases this size is a compromise, don't expect it to fall together and work like larger systems tend to do unless you follow exactly (and I do mean exact!) what someone else has achieved through trial and error. There's a lot of fudge room in a larger box compared to these and any deviation from what someone else has done can dramatically change how yours acts. I thought I had a pretty good plan based on research and yet here I am weeks later still toying with it and every little thing brings dramatic changes.
