If I can suddenly in coma for a year, wake up and pay my bills, it’s enough.

Humans are doomed, destroy themselves one way or another.

I remember trying Retroshare… no offline message is the biggest obstacle.

If the firewall just means no incoming connections, your computer can still reach out to the other side (if they open their port)

Important things about dual booting:

1. Configure your Windows to use UTC time https://wiki.archlinux.org/title/System_time#UTC_in_Microsoft_Windows

2. Disable “Fast startup” in Windows (can possibly cause hardware issues if not disabled and it really doesn’t improve things in computers with SSD)

What do you recommend I do about disk partitions?

I recommend separate EFI partitions while dual booting, I haven’t seem issues with my separate EFI partition setup yet.

If Mint provides Btrfs filesystem I personally recommend looking into timeshift (snapshot software that can be setup to automatically snapshot your computer).

Is disk encryption straightforward?

According to Linux Mint forum, you need to choose an option in “Advanced features” while going through installer, that seems straight forward

Is cloud storage sync straightforward?

Don’t have experience with this but I can tell you: While rclone supports bi-directional sync, you need some setup for make it run periodically.

Should I just use apt to install software?

In the end you have to give trust to someone, I think it’s fair to say if you already choose Mint you probably trust whatever options comes with Mint more than 3rd party options (but is it theoretically possible that backdoored program exists in Mint repository? of course yes).