A couple comments (which no one including Richard has asked for).
Definitely an upgrade from his former Dell laptop. The biggest issue I can see putting 2 computers in a small space of a closed cabinet. Doubt the streamer would generate too much heat, but the HW computer behind it, hmmmm. Of course the easy fix for that is simply to leave the cabinet doors open when playing the organ. The Samsung SM951 is a good choice for a small NVMe SSD probably used for the OS and for HW. I question the use of the WD 1TB HDD which is a mechanical drive. A better choice IMHO, would have been to use a single either a 1TB or 2TB SSD (NVMe) in place of the SM951.Something like a Samsung - 970 EVO Plus 1TB Internal PCI Express
Some question whether there would be a better choice for his audio card, Focusrite Scarlett 2nd generation 18i20 ??
On his editing setup, unless I miss my guess that (server) rig he's got won't be esp quiet. The AMD Ryzen Threadripper,while being lightning fast is a real monster requiring liquid cooling and big (noisy IMO) fans. (Never been an AMD "fan" plus the Thresdripper can be quite temperamental at times)..I admit, tho that I've not had first hand experience because I have no need of anything that big.
Everything else looks good, Any further thoughts, anybody ?
Rgds,
Ed