1 - I do.
2 - I'll have to check this when home
3 - Never had this issue
4 - It is a semi-manual process, it is not as integrated as anything with Dirac Live (like the miniDSP streamers) but it's pretty fully featured if you have the tools and experience to set it up. See my blog post on this.
https://speakermakersjourney.blogspot.com/2020/01/the-snr-1-room-response-and-roon.html5 - Yep, Roon requires a beefy core, but then streamers can be ridiculously cheap. I use an old Linux with an AMD A10 CPU for the core, an SSD for the music, and a Pi 4 for the streamer.
In my case, I dusted off the old Linux box, and got a Pi 4, so my hardware outlay was ~ $150.