I can only help really with number 2. But depends on platform. My understanding is Intel, ram speed isn’t as important. With AMD zen based chips, it matters more.
Also for capacity, take what you think you need. And add at least 50%. I built my server with 64GB thinking yeah that’s a lot. Should be plenty. Within 6 months I was looking at ram upgrade options because I needed more but don’t have space for a second server.
Quality Sample / Engineering Samples, are W.I.P. CPUs, at some milestone point or testing a property limit. If who’d you obtain this chip off of, can vouch its functionality - or where the chip may fall short to the latter retail release [exs. - cannot achieve projected boosting, reduced caches, etc.]
Not much of a major swing, to call a major improvement. Do keep tabs on your mainboard choice(s). Memory capacity / speed limits may vary, between mfrs
It is a larger HS, so the fan grows with assembly - in turn, noise should be tame out-of-box [+ fan curve adjustments, through the BIOS / outside software, be a quick work-around]. IF its a conventional size, say like a 92mm^2, with hole points matching - then you have options