I would also like to hear about other users experiences with the new Mac Mini i7 (Late 2018) specifically for Music Production. My usage is pretty similar to the OP and I would be very interested to hear about noise levels in particular as well as performance improvements.
I can't speak to mixing and bouncing performance yet, but what I can say is that live performance with software instruments and guitar amp sims has been awesome compared to my 2014 i7 Mini. The 2014's tendency to stutter or breakup with lower buffer sizes over a TB2 interface (especially when multitasking) was literally the #1 reason I ordered the 2018 i7 Mini the day it came out.
Now I can keep Logic open all day with my software instrument piano+MIDI keyboard, guitar plugged into audio interface into Logic guitar sim and have Facebook open and be playing Youtube videos while practicing guitar with 0 hiccups and low latency.
This Mini is so snappy I may move some of my software development workflow back to OSX.
As far as noise, the Mini's internal fan is not audible in my treated studio when performing the above live work in Logic. For reference, the Shuttle PC I have 3m away with a towel over it IS audible, as is my ceiling fan's motor. My development workstation (with a silent power supply and Noctua CPU cooler) is slightly audible and it sits opposite my Mini.