I also use it. Big benefit is also that you don‘t need a special software to access your backup.

If you have little Linux experience it makes no sense to use a niche distribution. You have a lot less people to ask for help, you will find less documentation and support and you will be frustrated really fast, because your niche distribution is doing something different than everyone else, which will break something and you cannot repair it. If you are a beginner go with one of the big ones.

There is already a sudo group. Just add a user to it and next time they log in they can use sudo.

I use cppcheck.

Research!

On POSIX systems there is the pthread library. Pretty easy to use. At least on Linux I think std::thread is just a wrapper for pthread.