In reverse order.
Yes you do have rights to your own work, but these huge companies baselessly think they have the right to works or pictures/videos on your device. FK them in the A, I hope they join a suicide cult, and good luck to them!
Making windows based live USBs is not what I call fun, never mind the countless hours configuring everything for each pc. Maybe the open source ReactOS will have more luck on that front when it reaches a higher point release.
NextCloud is a self hosted server that can be used for most things you would have used Google for. Check The Linux Gamers video on it. I basically followed that, and it ran out the box. Tho I've not setup my own e-mail.
I'd describe containers as sandboxed trees that can be mounted anywhere you like. It doesn't really matter what filesystem it uses so long as you can read it. I just search for whatever program i want and usually if its a common app youll find it. Docker is the one I've just started playing around with, and yes, it is available on pretty much any OS including Winblows.
Since I used Slax run from a USB drive, I would use modules which are basically zipped folders with the program installed to it and a text file describing where each file/folder is inserted to your system at boot. This is done automatically, or if it's in the Options folder you can run it by a switch after post.
The /dev folder has every device connected to the system referenced by a file for each device. I've noticed the mount points differ for different devices such as USB keys to internal HDDs sometimes in /Media others in /Mnt. It seems arbitrary and changes depending on what Distro you use.
Finally A-Z in windows. I cant understand why M$ continue to use this DOS legacy standard which makes no sense. I could mount every iso i have on my HDD to separate points and as far as i know there are no restrictions. If this was done on windows wouldn't it run out once all 26 letters are used? It just seems like an unnecessary restriction. Also, nowadays lots of computers only have one HDD and no floppy or CD drives, so why use C: as the default drive letter for the primary partition? It's almost as weird as pushing an update that erases peoples home folders without proper testing.
I only have the most basic understanding of most of this since i used Windows for way too long. Plus I probably end up getting the wrong end of the stick a lot of the time. I recon everyone will be the same at some point, but the trick is to keep reading up and testing things yourself, ask questions if you get stuck and most of all enjoy playing around .