1) I'd say don't worry about the partitions then, either keep practicing in the VM or get a flash drive and install Linux Mint on there that way you can boot from it on your computer and play around with it on your PC without worrying about partioning drives. Partitions can be tricky and can result in data loss so your hesitation is warranted.

There's also something to say about just diving in head first and making it work. When I was a kid I had Ubuntu as a dual boot and played with it a bit but it wasn't until I became an adult and went down the privacy rabbit whole that I did a complete switch and had to figure out quickly how to remake my workflows. Had I gone all in at an earlier age who knows where I'd be today.

2) Your IP isn't the only info webpages get when you visit them. Perhaps check out this article for details https://mullvad.net/en/browser/browser-fingerprinting if you go to fingerprint.com then note the visitor ID then change your VPN server, you'll not that on most browsers the website will recognize you as the same user. Fingerprint resistant browsers like Tor Browser or Mullvad make you look like other users of the same browser so the website gets lots of false positives increasing your anonymity.

It's good to note that this is mainly a desktop issue, mobile browsers have much more uniform fingerprints since each device has the same specs largely.

3) Yeah WiFi motion tracking is real and very accurate. Also with the PATRIOT act the federal government basically accesses everything your ISP knows without a warrant so it's extra dangerous.