Yes.
You have one roon core server and as many control points as you want.
It is strongly recommended to connect the core by wired ethernet. If you build a NUC perhaps you can put it near your router.
Yes that will be fine. You fire up the nuc server it gets a network address, then fire up the Mac and as they are sharing the same router (wired Vs wireless doesn’t matter) the Mac will find the nuc and ask if you want to use it as the core.
Keep asking questions, better to find out any problems now.
The Knowledge Base might help https://kb.roonlabs.com/
If you Move your music to the Nuc, easier if it’s on a usb drive or can also do an internal but it will need to be formatted in the Nuc if you use ROCK
I was kind of shocked but decided to separate core off my Mac mini. I had that with ssd and just using for roon. Directly plugged in Chord Hugo 2 into optical using Focal Utopia headphones. Figured with optical it wouldn’t make any difference.
Moving core to another Mac seems to open the sound a bit and add little more impact. I switched back and forth a few times just to make sure.