I'd get an 850W Titanium one from Seasonic. It goes like this: 8 disks make for 100W, the CPUs make for another 200, a graphics card my need 350 and then you may HBAs or RAID cards which can draw another 20W, plus a 10GB network that may be rated for 15W and a bunch of fans (like 7 or 8 depending on your case and another fan blowing on the cards) at 5W each is another 40W. You could get away with 750W but I wouldn't try that. Of course, that's like the worst case, but you get the idea.
The WD Red are utterly slow and I don't recomment them. You might find 2TB HGST Ultrastar (not Deskstar!) (even used on ebay).
You could go for a Noctua NH-U12DX i4 if you need it to be quiet. Dynatron makes nice coolers, too: https://www.dynatron.co/air-cooler?APPLICATION=3U%26UP&CPU Socket=LGA2011%2F2066%2FNARROW|LGA2011%2F2066%2FSQUARE
Which case did you get and does it come with fans?