manv :
A 1000W PSU might just work but you might be cutting it close. I would recommend you to use a PSU of slightly higher wattage like 1500W. You are ready to build a very expensive build. Why try to save a few dollars and get a lower wattage PSU which if insufficient to power your PC can lead to death of a lot of components? Give yourself more than a little bit of headroom when it comes to choosing an appropriate PSU.
Nonsense!
That's complete bs to be honest.
Even an 850w would run everything at stock speeds and allow for some OC, although I would recommend a 1000w PSU for the 6950x, because you can get some really good overclocks on that thing with a bit more voltage.
The RM series is not very good, because uses CapXon secondary capacitors, which are low quality, but if you already own it stick with it, perfectly fine to use, but I just wouldn't recommend buying it with better quality options out there!
If buying, I recommend something like the EVGA G2/P2 1000w, Corsair HXi or AX/AXi series if they are on sale, or anything else made by Seasonic or Superflower imo. If you have any queries, let me know.
In relation to your choice of storage, Seagate Barracuda drives are very budget oriented, and have a high failure rate year over year. Get the WD Black 2TB (high performance HDD) and a 500GB Samsung 850 Evo, better than the PNY drive.
In terms of cooler fans, the best for static pressure, which you'll want, are the Noctua NF-A14s, NF-F12s and the Fractal Design HP-12 and HP-14s.
Both are quiet while giving great performance.