Basic questions about iCloud Music

My apologies for these basic questions but I have tried searching on line and the end result is added confusion!

Also, I hope this is the right forum for iCloud music questions, I dont see one specific for that.

I have current versions of iOS, iTunes (Windows) and have joined Apple Music.

Some of these questions I think I may have the answer from observation but want to be 100% sure.

1. What is the difference between iCLoud music and iMatch (other than cost!)

2. Turning iCLoud music on does not delete files from the computer or mobile device?

3. If there are multiple versions of a track (different bit rates on different devices) do they all end up in iCLoud or just the highest bit rate.

4. Likewise what if the metadata differ (especially art work)?

5. Given that Im sometimes away from a WLAN (WiFi) I want to have a subset of my library on each mobile device (and all of it on the desktop of course). The subsets would differ due to the different capacities of the devices. Am I correct that the only way to do this is to sync with iCloud off?

6, Should it be off just for the mobile device or off on the desktop as well?

7. Turning iCloud music off on a device presumably deletes iCLoud items from the devices Music that are not actually on the device? But such tracks are still visible to other devices with iCloud on?

.....

Where I'm trying to get to is a master iTunes library on my desk top with highest quality (this is a slight over simplification as a good part of my library is FLAC but I clone an mp3 version of those files for iTunes) versions of all tracks. I then sync device specific subsets to each mobile device. And then make the entire library available through iCloud (turning back on on the mobile devices). Is this a reasonable approach?